Felson's Principles of Chest Roentgenology, Third Edition

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FELSON’S PRINCIPLES OF CHEST ROENTGENOLOGY ISBN-13: 978-1-4160-2923-6ISBN-10: 1-4160-2923-0

Copyright © 2007 by Saunders, an imprint of Elsevier Inc.

All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any informationstorage and retrieval system, without permission in writing from the publisher.Permissions may be sought directly from Elsevier’s Health Sciences Rights Department in Philadelphia, PA, USA: phone: (+1) 215 239 3804, fax: (+1) 215 239 3805, e-mail: [email protected]. You may also complete your request on-line via the Elsevierhomepage (http://www.elsevier.com), by selecting ‘Customer Support’ and then ‘ObtainingPermissions’.

Previous editions copyrighted 1999, 1965 by Saunders

Library of Congress Cataloging-in-Publication DataGoodman, Lawrence R. (Lawrence Roger)

Felson’s principles of chest roentgenology.— 3rd. ed. / Lawrence R. Goodman. p.; cm.

ISBN-13: 978-1-4160-2923-6ISBN-10: 1-4160-2923-0

1. Chest—Radiography. I. Felson, Benjamin. II. Title. III. Title: Principles of chest roentgenology.[DNLM: 1. Radiography, Thoracic—Programmed Instruction. WF 18.2 G653f 2007]

RC941.G56 2007617.5′407572—dc22

2006051198

Acquisitions Editor: Todd HummelPublishing Services Manager: Tina RebaneProject Manager: Linda Lewis GriggDesign Direction: Steven Stave

Printed in USA

Last digit is the print number: 9 8 7 6 5 4 3 2 1

Notice

Neither the publisher nor the author assumes any responsibility for any loss or injury and/ordamage to persons or property arising out of or related to any use of the material contained in this book. It is the responsibility of the treating practitioner, relying on independent expertise and knowledge of the patient, to determine the best treatment and method of application for the patient.

The Publisher

To my late parents,Martha and Sidney Goodman,

for years of support, encouragement, and loveand to my wife, Hannah,

and Roy, Julie, Sarah, and Noah

PREFACE

In speaking to students about the second edition of Felson’s Principles of Chest Roentgenology,I found that almost all of them wanted more unknown cases and more computed tomogra-phy. Yet they wanted the text to stay short and manageable. With the addition of a CD tothis third edition, the original text keeps its style, density, and length, while new material ison the CD as an option.

Cases! Cases! Cases! “We want more unknown cases.” I agree. Adding a CD made it easierto provide more cases without making the text too long. The CD also provides some interactivepossibilities. The extra cases have been divided into “structured unknowns”—-similar tothe “Quiz: A Dozen Great Cases “ in the text—-and “real world unknowns”—-with just historyprovided (sink or swim).

Interstitial Lung Disease. This topic drives everyone crazy. In “Interstitial Lung Disease: A Picture Book,” there are brief, pictured representations of various patterns.

More CT. There is a new chapter, “Chest CT: Putting It Together.” And more CT images havebeen added to the text and quizzes.

Rib Notching. In Felson’s original edition, the last chapter was “The Many Causes of RibNotching.” This always seemed to me an extra chapter he threw in at the end to bulk up thebook. It was quite good, however, and is now available on the CD.

Oral Boards in Chest. This section has been added to the CD to give advanced radiologyresidents a “taste” of the oral boards.

Thanks: Again, thanks to Ms. Sylvia Bartz, my senior administrative assistant, for her won-derful support and good counsel and to my wife, Hannah, for her encouragement and com-puter savvy. Thanks also to Professor Lorenzo Bonomo of the Universitá Cattolica in Rome.He provided warm hospitality and a quiet place for me to work on this third edition ofFelson’s Principles of Chest Roentgenology.

Lawrence R. Goodman

CREDITS

Figures

2-11 Dr. Andrew Taylor Medical College of Wisconsin, Milwaukee

2-12 Dr. Kiran Sagar Medical College of Wisconsin, Milwaukee

6-3 Dr. E. Martinez Prescott, Arizona

7-3A Ms. Ann Gorman Medical College of Wisconsin, Milwaukee

10-9 Dr. Melissa Wein Medical College of Wisconsin, Milwaukee

11-10 and 11-17 Dr. Sanford Rubin University of Texas, Galveston

11-4D Dr. Francisco Quiroz Medical College of Wisconsin, Milwaukee

12-12 The late Dr. Wylie Dodds Medical College of Wisconsin, Milwaukee

12-14 Dr. Emanuelle Fedrea Universitá delgi Studi di Milano, Milan, Italy

Q-12 Dr. Timothy Klostermeier Wilmington, Ohio

Board Review C-5 Lorenzo Bonomo Universitá Cattolica, Rome, Italy

S-39 Internet Scientific www.ispub.comPublications

Cartoons

Pages

105 Beetle Bailey Copyright King Features Syndicate

11, 43, and 65 Julie Goodman, MLA Brooklyn, New York

CD “Glossary of Terms for CT Radiology, with permissionof the Lungs: Recommendations of the Nomenclature Committee of the Fleischner Society,”

CD “Glossary of Terms for Am J Roentgenol, with permissionThoracic Radiology: Recommendations of the Nomenclature Committee of the Fleischner Society,”

Thanks to Messrs. Stanton and Barry Himelhoch (photographers) and Mr. Robert Fenn(illustrator) of Medical Center Graphics, Milwaukee, Wisconsin.

INSTRUCTIONS

Most of you are familiar with programmed learning. The numbered frames on the left sideof each page require a response. Questions are designed, in most instances, to help youmake the correct response: The answer is often made clear by the frame itself or by whatyou have learned in earlier frames. Answer by filling in the blanks or underlining wherethere are multiple choices. The answer to each frame will be found on the right side of thepage. Use the mask, on the back cover of the book, to hide answers to the frame. We preferyou to write your answers in ink so that your friends will have to buy their own copies.

It is not essential that your answers be identical to ours, so long as the meaning is the same.If you miss an answer, reread the frame so that you can be better prepared for what is tocome. It is okay to cheat by looking at the answers first, since it’s your money and time.Because your concentrated attention is required, we suggest that you set a limit of an hour,at most, of consecutive study.

At the end of each chapter is a Review Section summarizing the most important concepts.Don’t skip them. “A Dozen Great Cases,” the quiz that follows the last chapter, containscarefully selected x-rays that allow you to apply your new knowledge. If you don’t do well,blame us. I hope our attempts at humor and informality make the learning process pleasantand relaxing.

After you finish the text, there are supplemental chapters, additional unknowns, and a boardreview on a CD.

Before going to Chapter 1, try the samples below.

1This text is based on the reader’s participation.

(a) Mark Twain once said, “It is better to keep your mouthshut and appear [stupid/smart] than to open it and________________________.”

(b) Lee Rogers, MD, once said, “Don’t let the fear of being[right/wrong] interfere with the joy of being __________.”

(c) We expect you to adopt philosophy [a/b].

2Understanding the anatomy and the radiographic signs are thekeys to reading x-rays.

(a) “You’d be surprised how much you observe by ________________________” said Lawrence (Yogi) Berra.

(b) “You only see what you ______________________,” saysLawrence (Larry) Goodman, MD.

(c) This book was written based on assumption [a/b].

1

(a) stupid remove all doubt

(b) wrong right

(c) b

2

(a) watching

(b) know

(c) b (It’s my book!)

COMPACT DISKCONTENTS

A CD is included with this edition to provide additional material with-out interfering with the basic flow of the original text. When you finishthe text, take a look at the CD.

MORE UNKNOWN CASESA. Challenging Cases: Structured like A Dozen Great Cases QuizB. Sink or Swim: Brief history only, like the real world

Supplemental CHAPTER 1: SEGMENTAL ANATOMYThis is revised Chapter 5 of the second edition of Principles ofChest Roentgenology. Many people, including myself, thoughtit was more detailed than needed. It is here for those of youwho are interested in more detail.

Supplemental CHAPTER 2: INTERSTITIAL LUNG DISEASE FORTHE NOVICEUsing a series of pictures, x-rays, and CT scans, this is a pictorialexplanation of honeycombing, the reticular pattern, and thenodular patterns, etc.

Supplemental CHAPTER 3: THE MANY CAUSES OF RIB NOTCHINGThis chapter was in the first edition of Principles of ChestRoentgenology but was dropped from the second edition. It ismore than you need to know, but interesting. Try it if you havetime.

CHEST RADIOLOGY MOCK ORAL BOARDSThis a chance for senior radiology residents to try their handsat some typical cases presented at the oral boards with a clockticking in the background. The only things that are missing aretachycardia (yours) and an examiner sitting behind you, offeringyou no feedback. Give it a shot. (Note: Current boards maypresent more cardiac material than is presented here.)

“Glossary of Terms for CT of the Lungs: Recommendationsof the Nomenclature Committee of the Fleischner Society”

“Glossary of Terms for Thoracic Radiology: Recommendationsof the Nomenclature Committee of the Fleischner Society”

The CD is bound in the back of the book.

1

ONE

THE RADIOGRAPHICEXAMINATION

The chest x-ray and computed tomography (CT) are part of every physician’s practice. Youshould have a basic understanding of the anatomy and pathology visible on the images. In just 12 short, interactive (and occasionally humorous) chapters, you will learn a systematic approach to reading the normal anatomy of the thorax and the basic patternsof lung disease.

1Let’s start with the standard frontal view of the chest, the posteroanterior (PA) radiograph, or the “PA chest.” The term posterior/anterior refers to the direction of the x-ray beam, which in this case traverses the patient from _______________ to _______________.

2By convention, the routine frontal view is taken with the patientupright and in full inspiration. The x-ray beam is horizontal, and the x-ray tube is 6 feet from the film or detector. This iswhat you get when you order a _______________ view.

1

posterior (back); anterior(front)

2

posteroanterior or “PAchest”

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2 Felson’s Principles of Chest Roentgenology

FIGURE 1-1 A

FIGURE 1-1 B

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One • The Radiographic Examination 3

3The PA view is taken at a distance of ____ feet to reduce magni-fication and enhance sharpness. Placing the part to be x-rayedclose to the x-ray cassette (film receptor) also reduces magnifi-cation and increases sharpness. See for yourself: Place yourhand, palm down, 3 or 4 inches from a desktop, preferably undera desk lamp (bulb type). Observe the shadow.

(a) Flex your middle finger only. Its shadow gets [wider/narrower] and appears [sharper/less sharp]. That fingeralso appears foreshortened.

(b) If the light source (i.e., x-ray tube) moves further away,magnification [increases/decreases], and the marginsbecome [sharper/less sharp].

4To reduce the magnification and increase image sharpness, the chest should be as [close to/far from] the x-ray cassette as possible, and the x-ray tube should be as [close to/far from]the cassette as practical.

5The anteroposterior (AP) view is usually made with aportable x-ray unit on very sick patients, who are unable tostand, and on infants. The patient is supine or sitting in bed.In this instance, the x-ray beam passes through the patientfrom ______________ to _____________.

36

(a) narrower (less mag-nification); sharper

(b) decreases; sharper

4

close to; far from

5

anterior; posterior

The AP view is taken supine or sitting rather than prone because it is less awk-ward than a PA view for a sick patient, and an infant usually squawks lesswhen he or she can see what’s happening.

6Because portable x-ray units are less powerful than regular unitsare, and because space is tight at the bedside, AP views are usually taken at shorter x-ray tube-to-film (receptor) distance.Compared with the PA radiograph, the AP radiograph has[greater/less] magnification, and the anatomy appears [more/less]sharp. The heart is an anterior structure. It would seem largeron a(n) [AP/PA] image. Why? _______________.

6

greater; less; APThe heart is further fromdetector (film)

The PA upright is preferred to the AP supine view because (1) there is less magnifi-cation; (2) the image is sharper; (3) the erect patient inspires more deeply, showingmore lung; and (4) pleural air and fluid are easier to detect on the erect film.

7Figures 1-1A and 1-1B are two films of the same patient, one APand one PA. Which is the PA? How did you decide? _________.

7Figure 1-1A is the PASharper edges, lessmagnification, deeperinspiration

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FIGURE 1-2 A

FIGURE 1-2 B

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8The other routine view is the lateral. By convention, the left side of the chest is held against the x-ray cassette. This is called a ________________ view. Similar to the PA view, it isalso taken at ________________ feet.

8

left lateral6

Frontal radiographs, AP or PA, are viewed as if you were facing the patient. In Figure 1-2A, and in all x-rays, the patient’s left is to your right. The heart is onthe left. Right?

If we were consistent, we would call it a right-left lateral, but “a foolish consistency is the hobgoblin of little minds” (Emerson). We just call it a lateral view.

9It is often difficult to detect a lesion located behind the heart, near the mediastinum, or near the diaphragm on the PA view. The _____________ view generally shows such a lesion,so we use it routinely.

9

lateral

Figures 1-2A and 1-2B. The nodule, superimposed on the heart, is easily seen onthe lateral view. On the frontal (PA) view, it is hard to see along the left heartborder. (Figure 1-2B, metallic artifact = pajama snap; Figure 1-2A and 1-2B, linearartifact = intravenous catheter in superior vena cava.)

10On the lateral, which is routinely taken with the [right/left] sideagainst the cassette, a right-sided nodule appears [larger/smaller]than an identical left-sided nodule.

10leftlarger (magnified)

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FIGURE 1-3 A

FIGURE 1-3 B

FIGURE 1-3 C

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11In Figure 1-3A, the patient is in the right anterior oblique position.His [left/right] chest is against the cassette, and the radiographis taken in the [AP/PA] direction.

12When a patient turns from the straight PA to the right anterioroblique position, different anatomic structures move in differentdirections. In the right anterior oblique, the left pectoralismuscle or breast (anterior structure) moves [medially/laterally],and the left scapula (posterior structure) moves [medially/laterally], relative to the thorax. The opposite occurs in the leftanterior oblique.

13Oblique views can help us localize lesions and eliminate superimposed structures. Figure 1-3B is a PA radiograph showing a calcified (white) mass over the upper thorax on the patient’s [left/right]. In Figure 1-3C, in the right anterioroblique, the mass moves [medially/laterally], relative to thethorax. It must be located [anteriorly/posteriorly].

11

rightPA

12

laterallymedially

13

leftlaterallyanteriorly

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FIGURE 1-4 A

FIGURE 1-4 B

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14What other views are there? Free fluid in the pleural cavity is affected by gravity. Fluid gravitates toward the diaphragmwhen the patient is [erect/supine], toward the back when the patient is [erect/supine], and toward the lateral aspect of the dependent thorax when the patient lies on his or her ________________ in the lateral decubitus position.[Decubitus = lying down. Lateral decubitus = lying on the side. (I looked it up.)]

15Return to Figure 1-1A. The [left/right] diaphragm is higher. This is normal. Now, in Figure 1-4A, the [left/right] diaphragmappears higher. This is [normal/abnormal]. Gravity can help us find the cause.

16Figure 1-4B is taken in the __________ position. The [left/right]side is down. The x-ray beam is parallel to the x-ray table. There is now a white band between the left ribs and the ___________.This is due to ________________.Congratulations! This is your first x-ray diagnosis. The leftdiaphragm appears high because there is fluid between thelung base and the diaphragm.

14

erectsupine

side

15rightleftabnormal

16decubitus; left

lungpleural effusion

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FIGURE 1-5

FIGURE 1-6

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17Intrapleural fluid falls with gravity, whereas intrapleural air ___________. The ideal position to diagnose a pneumothorax(intrapleural air) is [erect/supine]. If you suspect a left pneumothorax in a patient, who can’t stand or sit, a lateraldecubitus film with the [left/right] side down is helpful. This iscalled the ____________ position.

17

riseserect

rightright lateral decubitus

Figure 1-5 shows a pneumothorax in the erect position (arrow delineates edge of lung). Figure 1-6, in a different patient, shows air between the lung and the leftribs in the right lateral decubitus position.

18The normal chest film is always made on [inspiration/expiration].On expiration, the lung markings become more crowded. Thereis less air in the lung, so the lung appears [whiter/blacker]. Theheart, which sits on the diaphragm, is elevated and appears[larger/smaller].

18inspiration

whiter

larger

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FIGURE 1-7 A

FIGURE 1-7 B

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19Figures 1-7A and 1-7B are PA radiographs of the same patient atthe same time. One is an inspiration and one is an expiration.The diaphragms are higher in [Figure 1-7A/Figure 1-7B]. Thelungs appear blacker in [Figure 1-7A/Figure 1-7B]. The heart andvessels appear bigger in [Figure 1-7A/Figure 1-7B]. Therefore,[Figure 1-7A/Figure 1-7B] is an expiration.

19

Figure 1-7AFigure 1-7BFigure 1-7AFigure 1-7A

Potential Pitfall: Expiratory films and AP supine films make the heart and vessels appear larger and the lungs whiter compared with a PA inspiratory film.These changes may simulate disease.

What causes the x-ray film to be black or white? An unexposed x-ray film is housedin a lightproof cassette, sandwiched between two phosphorescent screens. X-rayshit the phosphorescent screens, the screens give off light, and the light exposes thefilm. Heavy light exposure (e.g., through radiolucent lung) precipitates muchsilver, which causes the film to be black. Little light exposure (e.g., through radio-dense bone) precipitates little silver, which causes the film to be white. Film is nowbeing replaced by sophisticated digital receptors that offer many advantages; how-ever, the basic image formation remains the same. Digital data are more flexible;data can be transmitted, stored, and processed to alter contrast and brightness.(More technical stuff is in Chapter 6—try to resist peeking.)

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FIGURE 1-8 A

FIGURE 1-8 B

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20Expiratory films can be used to one’s advantage. An expiratoryfilm can be used to detect focal air trapping from asymmetricalemphysema or a partial bronchial obstruction that impedes airflow on expiration (air trapping). Because the air in theobstructed bronchus cannot be expelled readily, that lung (or lobe) remains [inflated/deflated] on expiration, while therest of the lung ____________, normally.

21On expiration with unilateral air trapping, a normal deflatedlung appears [whiter/blacker/unchanged], whereas an obstructedlung appears [white/blacker/unchanged].

20

inflateddeflates

21

whiterunchanged (remainsblack)

In Figure 1-8A, the right lung is slightly blacker than the left lung. In Figure 1-8B,an expiratory film, the left deflates normally and gets whiter, while the rightremains inflated and black. This was due to air trapping behind an aspiratedforeign body.

Clinical Pearl: If you hear a unilateral wheeze, order an expiratory film to lookfor air trapping.

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FIGURE 1-9 A-F

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22An expiratory x-ray may accentuate a small pneumothorax. On expiration, the deflated lung appears [whiter/blacker] compared with the black intrapleural air, and the fixed amountof intrapleural air is relatively [larger/smaller] in the smallerhemithorax. Logical? Yes. Helpful? Seldom!

23Let’s review the various radiographic positions. What views areillustrated in Figure 1-9A-F?

A. ____________ D. ___________B. ____________ E. ___________C. ____________ F. ___________

22

whiter

larger

23A. PAB. lateralC. right anterior obliqueD. APE. AP supineF. right lateral decubitus

Two older techniques, the apical lordotic position and tomography (laminography),were used to display areas obscured by overlapping structures. The apical lordoticradiograph is a frontal view taken with the x-ray beam angled upward to projectthe clavicles above the lung apex to display disease hidden behind the clavicles.Tomography is a complex technique that uses an x-ray tube and cassette that movein opposite directions, keeping only the area of interest in focus. Both techniqueshave been largely replaced by better quality chest radiographs and computedtomography (CT)—two fewer things you have to learn!

24All techniques discussed so far produce static images—a subsecond snapshot of the thorax. Fluoroscopy, which is a real-time x-ray viewed on a video monitor, provides informa-tion about moving organs. Examples include motion of the___________ during respiration and left ventricular ___________during systole. During fluoroscopy, the patient can be turnedobliquely, to eliminate _____________ of structures.

24

diaphragm or chest wallcontractionoverlapping (superiorposition

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FIGURE 1-10

FIGURE 1-11

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25Differential absorption and penetration of the x-ray photonscreate the x-ray image. [Direct/scattered] radiation exposes thefilm randomly, causing a background fog (loss of contrast),rather than useful information. In Figure 1-10, the image is formedby _____________ x-rays and degraded by ____________ x-rays.

26Bone absorbs [more/less] radiation, and air absorbs[more/less] radiation. Bone is said to be radiodense becauseradiation [hardly/easily] penetrates it. The lung is deemed radiolucent because radiation [hardly/easily] penetrates it.(Absorption = 1/penetration.)

27Scattered radiation [increases/decreases] contrast, degrading theimage. A grid (G) is a large thin plate composed of thin parallelstrips of metal and wood. As shown in Figure 1-11, the woodstrips permit most of the [direct/scattered] x-rays to reach thefilm, while the metal strips absorb many of the [direct/scattered]photons. [Figure 1-12A/Figure 1-12B] was taken with a grid. How did you decide?

25

scattered (deflected);

direct (penetrating);scattered (S)

26morelesshardlyeasily

27decreases

directscattered; Figure 1-12Asharper, less noisy

A few technical points: What causes the blacks, whites, and grays of an x-rayimage? The x-ray beam contains x-ray photons of differing energies. As the x-rayphotons pass through the patient, some are absorbed completely (A), some penetrate directly to the x-ray film (P), and some are deflected (scattered) (SS).Some of the scattered photons continue toward the x-ray film (S) (Figure 1-10).Absorption and penetration are the reciprocal of each other. The differentialabsorption of radiation by different tissues or diseases is responsible for allradiographic images. Air, fat, soft tissue (muscle, fluid), and metal (bone)absorb progressively more radiation. The thicker the tissue, the more it absorbs.

FIGURE 1-12 A FIGURE 1-12 B

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FIGURE 1-13

FIGURE 1-14

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REVIEW

IFor the sharpest, truest images, the patient should be as [closeto/far from] the cassette as possible. The x-ray tube should be[4 feet/5 feet/6 feet] from the cassette. The effects of scatteredradiation are minimized with a _____________.

IIWhich view or technique, other than the routine PA and lateral,would give the most information in the following situations?

(a) free pleural fluid on the right: _______________(b) suspected air trapping behind an endobronchial

tumor: __________________(c) suspected right pneumothorax in patient who can’t sit or

stand: ________________(d) bullet fragment, possibly in heart: _____________

IIIIn Figure 1-13, match density with letter:

(A) Air density ________________(B) Metallic density ___________(C) Soft tissue on face _________(D) Soft tissue—on edge _______

IVA. In emphysema, excess ____________ is trapped in the lung.

The air [absorbs/transmits] most of the radiation. The x-rayfilm appears excessively [dark/light] in the emphysematousregions.

B. Fluid (effusion, blood, pus) is more radiodense. It absorbs[less/more] radiation than a normal lung. The diseased areaappears [dark/light].

C. In Figure 1-14, match density with letter:(a) Normal ___________________(b) Emphysema _______________(c) Soft tissue/fluid ____________

D. The heart and the fluid (c) are the same radiodensity. Why isthe heart “whiter”?

I

close to6 feetgrid

II

(a) right lateral decubitus(b) expiratory

(c) left lateral decubitus

(d) fluoroscopy

III

(A) A(B) B(C) C(D) D

IVA. air

transmitsdark

B.morelight

C.(a) A(b) B(c) CThicker, absorbs moreradiation

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FIGURE 2-1 A

L

L

L

FIGURE 2-1 B

FIGURE 2-2

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23

TWO

CROSS-SECTIONALIMAGING TECHNIQUES

Three relatively recent imaging techniques, computed tomography (CT), ultrasound (US),and magnetic resonance imaging (MRI), have greatly improved thoracic imaging. In all conventional x-ray techniques, the x-ray beam passes through the patient, superimposingall structures in its path onto an x-ray film or detector (projection image). Cross-sectionalscanning techniques “slice” the patient open, providing a look “inside,” eliminating superimposition. These images are the product of multiple digital readings, from multipleangles, synthesized into a digital image. The digital data can be processed to improve tissuecontrast and brightness or to view the anatomy in various planes.

1All cross-sectional imaging can be viewed in the “axial, sagittal,coronal, or oblique planes.”

(a) An image perpendicular to the patient’s long axis is a(n)_____________ image.

(b) An image parallel to the patient’s lateral plane is a(n)____________ image.

(c) An image parallel to the patient’s frontal plane is a(n) ______________ image.

(d) All other images are _______________ images.

1

(a) axial

(b) sagittal

(c) coronal

(d) oblique

Figure 2-1A shows the axial (A), sagittal (B), and coronal planes (C). Figure 2-1Bshows the relationship of the sagittal, coronal, and oblique planes to the axialplane. Axial images are viewed as if you were looking up from below. The patient’sleft is on your right.

CT provides the most useful cross-sectional imaging of the chest. The patient issupine on a mobile table that passes through a cylindrical tunnel or gantry. In thegantry wall, an x-ray tube (T) revolves around the patient (Figure 2-2). The x-raybeam hits multiple small radiation detectors in the opposite gantry wall. Radiationis detected, quantified, and synthesized into a digital image. (Don’t ask how—it’squite complicated.)

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FIGURE 2-3 A

FIGURE 2-3 B FIGURE 2-3 C

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Two • Cross-Sectional Imaging Techniques 25

2The CT scanner routinely produces [axial/coronal/sagittal] images(Figure 2-3A). In Figure 2-3B, the same data set is reconstructedin the ____________ plane of the trachea. In Figure 2-3C, it isthrough the ___________ plane of the trachea. In Figures 2-3Band 2-3C, arrows point to an area of _____________.

2axial

coronalsagittal; tracheal narrow-ing or stenosis

The same digital data can be displayed in subsets to optimize the contrast foreach type of tissue. In the thorax, it is routine to look at images reconstructed toshow lung detail (“lung window”), mediastinal detail (“soft tissue or mediastinalwindow”), and bone detail (“bone window”).

3Figure 2-3A is a(n) [axial/sagittal/coronal] image reconstructedto show [lung/mediastinal/bone] detail, whereas Figure 2-4 shows[lung/mediastinal/bone] detail in the same patient. To achievethis, the patient was scanned [twice/once].

3axiallungmediastinalonce

FIGURE 2-4

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FIGURE 2-5

c

FIGURE 2-6 A

FIGURE 2-6 B

FIGURE 2-6 C

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4Radiography and CT use x-rays. By convention, the synthesizedCT image of the normal lung is black because the lung is radio __________. The bone is white because it is radio _____________. Muscle, water, and fat absorb progressivelyless radiation and are progressively [lighter/darker] shades of gray.

5Conventional radiographs are able to distinguish four basictissue densities. In order of increasing x-ray absorption, they are:

(a) air (c) ________________(b) _________________ (d) ________________

4

lucent (transmits)dense (absorbs)darker

5

(b) fat(c) soft tissue (water)(d) bone (metal)

CT has better contrast discrimination than conventional x-rays and more easilydistinguishes between muscle, fluid (e.g., blood, bile), and fat. CT density isexpressed in Hounsfield units (HU). The scanner is calibrated so that pure water =0 HU. Typical HU values are: lung = − 800, fat = − 80-120, fluid = 0, muscle = + 40,and bone = >+ 350. Figure 2-5 shows the various CT densities in HUs.

6Although [x-ray/CT] has better contrast discrimination, the heart,the vessels, the mediastinal structures, and the muscles aresimilar intermediate shades of gray. This soft tissue density isapproximately [− 40/0/+ 40] HU. Iodinated contrast medium isoften given intravenously during the scan to increase the radiodensity of blood. The heart and vessels absorb [more/less]radiation than surrounding structures and appear [white/black].

6CT

(+) 40

morewhite

Figure 2-6A is an axial CT scan emphasizing the soft tissue or mediastinal structures(“mediastinal or soft tissue windows”). In Figure 2-6B, intravenous contrastmedium was given during scanning. Note the change in the density of the aorticarch (A) and the superior vena cava (S). Figure 2-6C is a left anterior oblique two-dimensional reconstruction, from the same digital data. Note the radiodensecalcified (c) aortic plaque in Figures 2-6A and 2-6C.

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FIGURE 2-7

FIGURE 2-8 A

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7Axial images assume you are viewing the patient from[above/below]. The patient’s right is on your left (as in the chestx-ray). In Figure 2-7, the [right/left] lung is normal. The branchingstructures that taper peripherally are the ______________. The radiolucent areas are the air-containing lung parenchyma.The ______________ lung contains a tumor. It absorbs [more/less]radiation than normal lungs. The tumor is radio ____________.

8Computers that are more powerful create images that are morepowerful. They create three-dimensional images that can beviewed from any direction. Figure 2-8A is a three-dimensionalview of the aorta. Compare with the two-dimensional recon-struction of the same aorta (Figure 2-6C). The same data set used for Figure 2-3 provides a three-dimensional view of the ____________ in Figure 2-8B. This is virtual bronchoscopy.

7

belowleftpulmonary vessels

right; moredense

8

trachea (carina)

Radiography and CT produce images based on the differential absorption of ionizing radiation by different substances. MRI uses an entirely different set of physical properties. To oversimplify, the patient is exposed in a gantry to ahigh-intensity magnetic field, and radiofrequency pulses are applied. Images arebased on the absorption and emission of radiofrequency energy. Different kindsof pulses create different kinds of images so that a substance that appears whiteon one set of images may appear black on a different set of images. Multiple setsof images are acquired with each study, and the combined information from allof the different images helps characterize tissues. These different sorts of imagesmay be referred to as weighted images depending on which characteristics of tissue are brought out by each “pulse sequence.” Images may be described asrelatively T1-weighted or T2-weighted. It is not necessary to learn what T1 and T2 mean, but it may be helpful to know that simple fluid tends to be bright on T2-weighted images and dark on T1-weighted images. (Note: Cerebrospinal fluidis bright on T2-weighted images.)

FIGURE 2-8 B

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FIGURE 2-9 A

FIGURE 2-9 B

FIGURE 2-10 A

FIGURE 2-10 B

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9The gray scale (blacks, whites, and grays) of MRI [does/does not]correspond to the densities of x-ray images. One would have toknow which __________ was used to understand the gray scale.Fluid tends to brighten on [T1/T2].

9does not

imaging sequenceT2

Figure 2-9 shows two MRI sequences of the same patient, with a right middlemediastinal mass. In the axial image, Figure 2-9A, the paratracheal mass isintermediate signal (i.e., gray) (white arrow). In the coronal image, Figure 2-9B,the paratracheal mass is high signal (i.e., white) (white arrow). Note the lowsignal (i.e., dark gray) in the lung and trachea and low signal in the spinal fluid(black arrow).

MRI has the advantage of avoiding ionizing radiation and iodinated contrastmaterial. The gadolinium-based contrast materials used in MRI also are muchless likely to cause adverse reactions. MRI is contraindicated, however, forpatients with pacemakers, defibrillators, and a wide variety of implanted metal-lic clips or devices. Each MRI sequence is relatively time-consuming, and multi-ple sequences are necessary for each examination. Patients often experienceclaustrophobia in the tubelike MRI gantry. MRI tends to be better able to answerspecific questions than to provide a broad survey of anatomy because of thewide variety of available pulse sequences. It is generally less valuable for imag-ing the lung than CT because the air within the lung provides relatively little MRIsignal. MRI is best used for imaging of the heart and vascular structures and toanswer a wide variety of neurologic, musculoskeletal, and abdominal imagingquestions.

10In Figures 2-10A and 2-10B, MRI scans were acquired throughthe left ventricle during the cardiac cycle. Left ventricular systole is depicted in [Figure 2-10A/Figure 2-10B]. How did you decide? _______________

10Figure 2-10A

The left ventricular wallis thicker; the chamber issmaller

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FIGURE 2-11 A

FIGURE 2-11 B

FIGURE 2-12

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11US is particularly valuable for evaluating [pneumothorax/empyema]. A simple pleural effusion (transudate) shows a lowand [heterogeneous/homogeneous] signal. Figures 2-11A and 2-11Bare US of the pleural space. The diaphragm (arrow) separates theliver (L) from the pleural space. Note the signal difference betweenthe transudate (T) and an empyema (E).

11empyema

homogeneous

In ultrasound (US) or sonography, a transducer directs high-frequency sound wavesinto the body, much the way the Navy uses sonar. The sound waves reflect differ-ently off different tissues. The transducer detects reflected sound waves and synthesizes them into diagnostic images. Fluid causes minimal reflection, so itappears as a homogeneous low-signal area (low echogenicity). Soft tissue absorbs,reflects, and deflects the signal, causing a heterogeneous echogenic area. Soundwaves travel poorly in air and bone. Bone-soft tissue and air-soft tissue interfacesare hyperreflective. Air-filled lung and bone are difficult to evaluate with US. US is relatively inexpensive, portable, and especially suited for imaging pleural or pericardial fluid and cardiovascular structures in real time.

MRI and US are capable of rapid repetitive image acquisition. This permits evaluation of dynamic physiologic processes such as cardiac motion and bloodflow. Figure 2-12, an echocardiogram (US), shows the four cardiac chambers.(LA = left atrium; LV = left ventricle; RA = right atrium; RV = right ventricle.)

12Match the clinical problem with the best imaging modality:

A. pleural effusion ____________________ MRIB. emphysema ________________________ USC. cardiac function ____________________ neitherD. tumor invading mediastinum ________ either

12

A. USB. neitherC. eitherD. MRI

Now that you are in medicine, it is certain that at some family gathering, AuntRose will ask you, “Exactly how safe is x-ray?” As with most important things,there are no simple answers. Diagnostic levels of radiation are generally consideredsafe for the individual, with the potential diagnostic benefits outweighing the barelymeasurable, but real, population risks associated with diagnostic levels of ionizing radiation. The major risks are genetic damage and potential cancerinduction. Conventional chest radiographs produce very, very low radiationexposure, whereas studies such as CT, fluoroscopy, and angiography give considerably higher doses. Radiation dose is cumulative over a lifetime (unlikean old love affair, it doesn’t “wear off” with time). Patient radiation dose shouldbe kept to a minimum. This is especially true during the reproductive years,during pregnancy, and during childhood because rapidly dividing cells are moresensitive to radiation damage. The best way to reduce patient exposure is tochoose the correct imaging examination. If you are unsure, discuss it with theradiologist.

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FIGURE 2-13

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REVIEWI

Conventional radiographs distinguish four basic tissue densities: __________, ________, ____________, and ___________.[CT scans/radiographs] have better contrast discrimination.

IIUS of a pericardial effusion (transudate) would be expected to be [homogeneous/heterogeneous] and have [low/high]echogenicity, whereas a loculated pericardial infection would be[homogeneous/heterogeneous] and of [low/high] echogenicity.

IIIThe CT scan in Figure 2-13 shows multiple intrathoracic densities.Match the areas with their approximate Hounsfield units:

A. normal left lung _________ + 350 HUB. pneumothorax __________ + 40 HUC. lung mass ______________ 0 HUD. calcified diaphragm _____ − 800 HUE. pleural effusion _________ − 1000 HUF. dome of diaphragm _____G. vertebra _______________

IVWho was Godfrey Hounsfield? ____________.

VDiagnostic radiation should be held to a minimum in (check oneor more):

(a) children(b) cancer patients(c) pregnant women(d) lawyers

Iair; fat; tissue (water);metal (bone)CT scans

II

homogeneous; low;

heterogeneous; high

III

A. − 800 HUB. − 1000 HUC. + 40 HUD. + 350 HUE. 0 HUF. + 40 HUG. + 350 or more

IVHe won the 1979 NobelPrize for Physiology orMedicine for develop-ing CT, shared withAllan M. McCormack.

Vall, even lawyers

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FIGURE 3-1 A

FIGURE 3-1 B

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37

THREE

THE NORMAL CHESTX-RAY: READING

LIKE THE PROS

The keys to reading x-rays well are a good understanding of normal anatomy and an orderlysearch pattern. This chapter reacquaints you with the normal anatomy and helps youdevelop a search pattern that you can apply to every radiograph. By being systematic, youwill miss fewer important findings—not that experienced hands don’t miss findings; theyjust miss fewer findings. Learn this ordered approach and then stick to it case after case.You will look like a pro.

1If you cannot tell a patient’s left from right, you will look like a[pro/turkey]. A PA or an AP x-ray is always viewed as if you arefacing the patient from the [front/back].

2You already know most of the anatomy; you just haven’tthought about it in terms of a PA and a lateral projection. With projection images, all anatomic structures in the x-raybeam are ____________. Mentally, you must fuse two projectionimages (PA and lateral) into a three-dimensional understandingof the anatomy.

3Test yourself on Figures 3-1A and 3-1B. Study these diagramsuntil you could give these answers in your sleep (perhaps youare already doing that).

Posterior/anteriorA. ___________ D. ___________ G. ___________B. ___________ E. ___________ H. ___________C. ___________ F. ___________ J. ___________LateralA. ___________ D. ___________ G. ___________B. ___________ E. ___________ H. ___________C. ___________ F. ___________ J. ___________

1

; front

2

superimposed

3

A. costophrenic sulcus(angle)

B. left diaphragmC. heartD. aortic knob (arch)E. tracheaF. hilumG. carinaH. stomach bubbleJ. ascending aorta

�Now turn the page, and redo with real films.

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FIGURE 3-2 A

FIGURE 3-2 B

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Three • The Normal Chest X-Ray: Reading Like the Pros 39

4Label radiographs in Figures 3-2A and 3-2B.

PA radiographA. __________ E. ___________B. __________ F. ___________C. __________ G. ___________D. __________ H. ___________Lateral radiographB. __________ H. ___________C. __________ J. ___________D. __________ K. ___________E. __________

4A. gas in splenic flexureB. costophrenic sulcus

(angle)C. heartD. descending aortaE. tracheaF. carinaG. hilumH. aortic knobJ. ascending aortaK. right diaphragm

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FIGURE 3-3 A

FIGURE 3-3 B

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7Arrange the following in viewing sequence:

A. mediastinum ________ D. lungs—bilateral ______B. lung—unilateral ________ E. thorax ______C. abdomen ________

Memory jog: Are There Many Lung Lesions?

7Correct sequence:A. 1—AbdomenB. 2—Thorax (soft

tissues and bones)C. 3—MediastinumD. 4—Lung—unilateralE. 5—Lungs—bilateral

To maximize your accuracy, you must have an organized search pattern. Startreading every radiograph—chest or otherwise—by scanning the areas of leastinterest first, working toward the more important areas. You are less likely tomiss secondary but important findings this way. For the chest x-ray, start in theupper abdomen, then look at the thoracic cage (soft tissues and bones), then themediastinal structures, and finally the lung. Look at each lung individually, thencompare left lung and right lung.

Abdomen: In Figure 3-3A, start in the right upper quadrant (*) and scan acrossthe upper abdomen several times. Normal gas-containing structures are thestomach and the hepatic and splenic flexures of the colon. The liver is alwaysvisible, and the spleen is often visible.

8Scan the abdomen in Figure 3-3B.

A. The gas collection just below the heart = ___________.B. The gas collection lateral to A = ____________.C. The homogeneous density below the right diaphragm

= ______________.D. The right diaphragm is higher. This is [normal/abnormal].

8

A. stomach bubbleB. splenic flexure of

colonC. liverD. normal

Clinical Pearl: Upper abdominal disease (subphrenic abscess, perforated viscus,pancreatitis, and cholecystitis) may mimic lung disease clinically. Similarly,basilar lung disease (pneumonia, pleurisy) may mimic upper abdominal disease.This is real!

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FIGURE 3-4 A

FIGURE 3-4 B

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9In Figure 3-4B, identify the following structures:

A. ____________B. ____________C. ____________D. ____________E. ____________F. ____________G. ____________

9

A. right breastB. posterior ribC. scapulaD. clavicleE. anterior ribF. stomach bubbleG. liver

Thorax: In Figure 3-4A, start at the right base (*), looking at the soft tissues (e.g., muscles, breast) of the chest wall, the ribs, and the shoulder girdle insequence. Finish by reversing the order down the left side. These structures arerepresented in Figure 3-4B. Note that the posterior ribs tend to be horizontal,while the anterior ribs descend from lateral to medial.

Tombstone of the Village Hypochondriac

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FIGURE 3-5 A

FIGURE 3-5 B

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10On Figure 3-5C, identify the following structures in the order ofyour mediastinal search:

1. _____________2. _____________3. _____________4. _____________5. _____________6. _____________7. _____________

10

1. trachea2. carina3. aortic knob (arch)4. ascending aorta5. descending aorta6. heart7. right hilum

Mediastinum: An organized search of the mediastinum is complicated becausethere are multiple overlapping structures. Start with a global look at the mediastinum for contour abnormalities (i.e., focal or diffuse widening). Figures 3-5A and 3-5B show three rapid searches of the mediastinum: A = for thetrachea and carina; B = for the aorta and heart; C = for the hilum.

Note that the left hilum is normally slightly higher than the right.

FIGURE 3-5 C

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FIGURE 3-6 A

FIGURE 3-6 B

FIGURE 3-7 A

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11See anything abnormal in Figure 3-7A? The abnormality is subtle.Compare side to side. The change should be obvious (it is to meanyway). There is a nodule in the _____________.

11right midlung laterally,over fourth anterior rib(Who said this would beeasy?)

Lungs: Most chest x-rays are ordered to evaluate lung disease, so the lungs areexamined last. The lungs are so important that we search them twice. Start inthe right costophrenic angle (*) as outlined in Figure 3-6A, examining the rightand then left lung. The second look involves a side-by-side comparison of thelungs (Figure 3-6B). This also should give you a second look at costophrenicangles and the hilum. Practice this search pattern in Figure 3-7A. Are ThereMany Lung Lesions?

Clinical Pearl: The old x-ray is your best friend. Radiologists always look at oldfilms when available. You should, too. They help you detect new disease andevaluate for change in preexisting disease. In Figure 3-7B, obtained 1 year earlierthan the x-ray in Figure 3-7A, the nodule was barely visible (arrows).

How do you tell who looked at the images last? A radiologist: The PAs and lateralsare in chronologic order. An internist: The PAs are in chronologic order, and thelaterals are in random order. A surgeon: All are in random order. An orthopedist:Half are missing.

FIGURE 3-7 B

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FIGURE 3-9

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12For the novice, subtle, and not so subtle, abnormalities are easy to miss. In searching the lungs, three helpful strategies to minimize oversights are (1) searching the lungs individually,(2) searching the lungs ______________, and (3) taking advantageof ______________, if available.

12

side-by-sideold radiographs

The lateral is a valuable but often ignored radiograph. Don’t ignore it! Thesearch pattern is identical (ATMLL). In Figure 3-8A, start by searching below thediaphragm (A). Continue at the lower spine (B), searching the soft tissues andbones posteriorly, then anteriorly (C). Return to the trachea and work your waydown the mediastinum (D). In Figure 3-8B, crisscross the superimposed lungsand costophrenic angles (E).

13Repeat the search in Figure 3-9. This patient is complaining of [dyspnea/cough/back pain] because of a ________________.[Actually, you would need a frontal image to know it was inside,not alongside the chest. This was inside.]

13

back pain; knife in back

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FIGURE 3-10

FIGURE 3-11 A

FIGURE 3-11 B

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14A bit of terminology about the lung parenchyma before we proceed. You have probably heard the terms “alveolar” and“interstitial lung disease.” This terminology causes the mostconfusion among nonradiologists and dyspepsia among semanticpurists. In the simplest terms, the lung parenchyma consists of air sacs and supporting structures. These air sacs are called ______________, they contain air, and they are [radiolucent/radiodense] on x-ray. Figure 3-10 shows alveoli arranged intoacini around terminal airways. Several acini form a secondarypulmonary lobule, the basic unit of lung function and grossmorphology.

15Supporting the alveoli are vessels, lymphatics, bronchi, andconnective tissue. This support framework is known collectivelyas the ______________ of the lung. On a normal chest x-ray, thebranching pulmonary arteries and veins are our only look at the interstitium. They appear white. They branch and taper andbecome invisible in the outer third of the lung—not becausethey don’t exist, but because they are _________________.

16If a disease affects only the interstitium, the interstitial tissuearound the small vessels or interlobular septa [thickens/thins],and they become [more visible/less visible] at the periphery of the lung. Because the air in the alveoli is hardly affected, the lung still appears well aerated.

14

alveoli; radiolucent(black) (invisible)

15

interstitium

beyond the resolutionof the x-ray or CT (“tootiny” for you nonsciencemajors)

16

thickensmore visible

Figure 3-11A shows thickened interstitium and normal aeration. Compare withnormal interstitium in Figure 3-10.

17If fluid or tissue (e.g., blood, edema, mucus, tumor) fills the airsacs, the lungs become [radiodense/radiolucent]. The interstitialmarkings are [more/less] visible within the alveolar consolidation.The lungs appear homogeneously white. They are not aerated.Figure 3-11B shows alveolar or airspace consolidation, whereasFigure 3-11A shows _________________.

17

radiodenseless

interstitial thickening

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FIGURE 3-12 A

FIGURE 3-12 B

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18Let’s build on Figure 3-11. In Figure 3-11A, the alveoli are aerated(black) and the interstitium is more prominent (white). The corresponding x-ray example of interstitial lung disease wouldbe [Figure 3-12A/Figure 3-12B]. Why? ___________. Figure 3-11Band Figure 3-12B are a match. Both show _____________.

18

Figure 3-12AProminent markings,aerated lungsAirless lung obscuringnormal anatomy in thelung apex (alveolar con-solidation)

That’s it, alveolar and interstitial disease—grossly oversimplified—but a good placeto start. Try to analyze each abnormal x-ray with these patterns in mind.

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FIGURE 3-13

FIGURE 3-14

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REVIEW

IChest x-ray reading sequence:

A = ______________T = ______________M = ______________L = ______________L = ______________

(Are There Many Lung Lesions?)

IIWith the interstitial pattern, the lungs appear well [aerated/consolidated], but the lung markings are __________________.Conversely, with the alveolar pattern, the individual lung markings are _________________ because the surrounding lungis ________________.

IIISearch Figure 3-13 systematically. Then answer the followingquestions below.

A. Which lung is more radiolucent? ________________B. What is the cause of the density difference? __________

(Hint: Is this a male or female?)

IVThis patient has chest pain and some difficulty breathing. SearchFigure 3-14 systematically. Then answer the following questions.

A. The lungs are ______________.B. The only radiographic finding is ______________.C. The patient’s pain is due to _____________.

(If you got these answers, great, you searched systematically. If not, review questions 7-12.)

I

AbdomenThoraxMediastinumLung—unilateralLungs—bilateral

IIaerated; thick (moreprominent); invisible(hidden); airless (consol-idated) (radiodense)

IIIA. right (blacker, less

radiation absorption)B. right mastectomy;

there is less x-rayabsorption and morefilm blackening onthe right

IV

A. normalB. free air under

diaphragmsC. perforated stomach

or bowel

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FIGURE 4-1 A

FIGURE 4-1 BFIGURE 4-1 C

FIGURE 4-1 D FIGURE 4-1 E

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57

FOUR

CHEST CT: PUTTINGIT TOGETHER

A chest x-ray is a two-dimensional summation image. We spend time synthesizing the superimposed anatomy on the PA and lateral into a three-dimensional understanding. CT isthe opposite task. The anatomy is not superimposed. We have to integrate the axial imagesmentally to get the overall picture. Your knowledge of the radiographic anatomy will helpyou understand CT scans. Conversely, CT anatomy will help you better understand radiographic anatomy. First, we need to master the CT anatomy and then develop ways to integrate the information.Every CT scan starts with a scout view, a projection image that looks like a second-rate x-ray.As you scroll through the axial images on a monitor, a line on the scout view tells you thelevel you are at. Figure 4-1A shows that the axial images (Figures 4-1B through 4-1E) weredone at the level of the aortic arch.

1(a) The lungs are best seen on Figure 4-1 ____________.(b) The mediastinum is best seen on Figures 4-1 ___________

and 4-1 ___________.(c) The bones are best seen on Figure 4-1 _____________.

2Figures 4-1B and 4-1E are mediastinal windows. Intravenouscontrast medium was administered in [Figure 4-1B/Figure 4-1E].How did you know? __________________.

3Let’s start by analyzing the mediastinum. It is easier to under-stand the anatomy [with intravenous contrast medium/withoutintravenous contrast medium]. So, we will learn with intravenouscontrast.

1(a) C(b) B and E

(c) D

2

Figure 4-1EThe vessels are whiter.(That is, they absorbmore radiation afterintravenous contrastinjection.)

3

with intravenous con-trast medium

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FIGURE 4-2 A

FIGURE 4-2 B

FIGURE 4-2 C

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Four • Chest CT: Putting it Together 59

4Figure 4-2A is called a(n) _________________. The three linesindicate the scan locations of Figures 4-2B, 4-2C, and 4-2D.Identify the following:

(a) ________________________(b) ________________________(c) ________________________(d) ________________________(e) ________________________(f) ________________________(g) ________________________(h) ________________________(i) ________________________(j) ________________________(*) ________________________

5The thymus is a soft tissue triangle in front of the ascending aorta.Like everything else after 40, it turns to _____________.

4Scout view(a) superior vena cava(b) aortic arch(c) thymus(d) trachea(e) ascending aorta(f) descending aorta(g) main pulmonary

artery(h) right pulmonary

artery(i) left ventricle(j) right ventricle(*) esophagus

5

fat

The pleura and pericardium also are seen on the mediastinal windows in Figure 4-2D. The pleura is seen as a very thin white line lining the thoracic cavity(posterior arrow). The pericardium sits between two layers of fat as it encirclesthe heart (anterior arrow). Normally, there is no visible fluid in the pleuralspace, but there may be some fluid in the pericardial space.

Encyclopedia Britannica—unused. Have two teenagers who knoweverything.

FIGURE 4-2 D

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FIGURE 4-3 A

FIGURE 4-3 B

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6Figure 4-3A shows [lung/mediastinal/bone] windows. Theanatomy is easy. The linear white branching structures are the _________. The black tubular structures with white bordersare the ___________. In the periphery, they [enlarge/disappear].Small vessels and bronchi are beyond the resolution of the CT image.

7When a CT image is perpendicular to a vessel or bronchus, it appears as a [circle/line].

8The area between the vessels is the lung parenchyma. The lungis mostly [soft tissue/water/air]. It is [radiodense/radiolucent]and appears [black/white].

9In Figure 4-3B, identify at lung windows:

(A) ______________________(B) ______________________(C) ______________________(D) ______________________(E) ______________________

10In Figure 4-3B, the thin white lines (D) are the major fissures.They are formed by the [visceral/parietal] pleura covering the individual lobes.

6lung

arteries and veinsbronchi; disappear

7

circle

8air; radiolucent (absorbslittle radiation)black

9(A) left pulmonary artery(B) pulmonary artery or

vein(C) right main stem

bronchus(D) major fissures(E) normal parenchyma

10

visceral

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FIGURE 4-4 A

FIGURE 4-4 B

FIGURE 4-5

FIGURE 4-6

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11Figures 4-4A and 4-4B are through the same anatomy. [Figure 4-4A/Figure 4-4B] is a high-resolution image. To achieve the high resolution, the image is [1.25 mm/2.5 mm/5 mm] thick recon-structed with an algorithm that [blurs/sharpens] edges. Note thedifference in detail.

12Pop Quiz: Tissue Density on CT

A. Lung = [−800/−500/+500/+800] HUB. Fluid = [−200/0/+50/+2000] HUC. Liver = [−400/−40/+40/+400] HUD. Bone = [−350/−35/+35/+350] HU

13To look at the bones, we use _______________ windows.

14The ribs are difficult to follow because they run obliquelythrough the axial images. Other bones are easier to follow. OnFigure 4-5, identify at bone windows:

(A) ___________________(B) ___________________(C) ___________________(D) ___________________(E) ___________________

15The upper abdomen is visible at mediastinal windows on theimages through the lung bases and the diaphragms (Figure 4-6).It is an unrequested bonus, but is often helpful.

(A) ___________________(B) ___________________(C) ___________________(D) ___________________(E) ___________________(F) ___________________

11Figure 4-4A

1.25 mmsharpens

12

A = −800B = 0C = +40D = +350

13boneIf you missed this, youmay want to return thebook for a refund.

14

(A) rib(B) sternum(C) scapula(D) vertebral body(E) spinal canal

15

(A) stomach(B) liver(C) spleen(D) splenic flexure(E) diaphragm(F) left lower lobe (lung)

High-resolution CT: To maximize lung detail for evaluating fine interstitial lungdisease, we use two strategies: We take thinner sections (1.25 mm instead of 2.5 or 5 mm), so there is less overlap with adjacent tissue (i.e., volumes averaging),and we use CT image reconstruction algorithms that sharpen edges.

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FIGURE 4-7

FIGURE 4-8 A

FIGURE 4-8 B

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16The best of both worlds: With high-end CT equipment, the axial images are very thin (0.5-2 mm thick versus 5-10 mm thick).High quality axial images can be reconstructed in any planedesired, giving us alternative looks at the intrathoracicanatomy. Review Figure 4-7. Plane A is the [axial/sagittal/coronal]plane. Plane B is the [axial/sagittal/coronal] plane. Plane C is the[axial/sagittal/ coronal] plane.

17Figure 4-8A is a [lung/mediastinal/bone] window in the[axial/coronal/sagittal] plane. It is lateral to the heart and greatvessels.

18Figure 4-8B is a [lung/mediastinal/bone] window. It is[axial/coronal/sagittal]. It is thought to be [the carina/the lungonly/both ventricles].

16

axialsagittalcoronal

17lungsagittal (parasagittal)

18lungcoronalthe carina

For Sale: Tombstone—great deal for anyone named K. P. Brzywanoski III.

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FIGURE 4-9 A

FIGURE 4-9 B

FIGURE 4-10 AFIGURE 4-10 B

FIGURE 4-10 C FIGURE 4-10 D

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19We finished Chapter 3 by discussing the plain film appearanceof alveolar and ___________ patterns of disease. Figure 4-9A is adiagram of air in the alveoli (black) and the normal interstitium(white), which compares with a normal high-resolution CT scan(Figure 4-9B).

20With alveolar consolidation, the lung is [airless/well aerated].The lung is [white/black]. It is said to be [radiodense/radiolucent].

21With interstitial disease, lung aeration is [almost normal/markedlydiminished/absent]. The interstitial markings (pulmonary vessels, bronchi, and connective tissue) are [more/less] promi-nent than normal.

22Figure 4-10A represents alveolar consolidation, and Figure 4-10Brepresents an interstitial pattern. Figure 4-10C represents an [alveolar/interstitial] pattern. Figure 4-10D represents an[alveolar/interstitial] pattern. Figure 4-10E represents an [alveolar/interstitial] pattern.

19

interstitial

20airlesswhite; radiodense(absorbs radiation)

21almost normal

more

22

interstitialalveolarinterstitial

FIGURE 4-10 E

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FIGURE 4-11 A

FIGURE 4-11 B

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REVIEW

IFor Figures 4-11A, 4-11B, and 4-11C:

A. Sagittal = _________________.B. Coronal = _________________.C. Axial = ____________________.

IIFor Figures 4-11A, 4-11B, and 4-11C:

A. Lung window = __________________.B. Mediastinal window = ____________.C. Bone window = __________________.

IIIFor Figures 4-11A, 4-11B, and 4-11C:

A. There is a focal density in the ______________ lobe.B. It is an example of [alveolar/interstitial] consolidation.

IVWhat might this represent in a:

A. 20-year-old man? _________________B. 68-year-old man? _________________

I

A. Figure 4-11BB. Figure 4-11CC. Figure 4-11A

II

A. Figure 4-11CB. Figures 4-11A and

4-11BC. none

III

A. right upperB. alveolar

IV

A. focal pneumonia or inflammatoryprocess

B. lung cancer

FIGURE 4-11 C

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FIGURE 5-1 AB

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71

FIVE

LOBAR ANATOMY

A “fingertip” knowledge of lobar and segmental anatomy is indispensable for understandingpatterns of lung collapse and patterns of lung disease. Some diseases have lobar or segmentaldistributions; others do not. Understanding the lobar anatomy also is important for planningbronchoscopy, surgery, radiation therapy, and postural drainage.

1The inner thoracic wall is lined by the _______________ pleura,while each lobe is surrounded by the _______________ pleura.The space between the visceral pleura and parietal pleura iscleverly named the _______________.

2The space between the lobes, where the _______________ pleu-ral surfaces touch, is called the interlobar fissure. Because thevisceral pleura is less than 1 mm thick, the x-ray beam muststrike it parallel to its surface if it is to be visible on the radio-graph. If a fissure is [parallel/perpendicular/oblique] to the x-ray beam, it will not be visible.

3In Figure 5-1A, the x-ray beam is [perpendicular/parallel] to thefissure or septum. The fissure [will/will not] be visible on theradiograph.In Figure 5-1B, the x-ray beam is [perpendicular/parallel/oblique] to the visceral pleural surfaces. The fissure [will/willnot] be visible on the radiograph.

1parietalvisceral

pleural space

2visceral

perpendicularor oblique

3parallelwill

obliquewill not

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FIGURE 5-2 A

FIGURE 5-2 B

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Five • Lobar Anatomy 73

4We challenge you to test your anatomic recall:

(a) Which lung is smaller? _______________.(b) Name the lobes of the right lung. _______________,

_______________ and _______________.(c) Name the lobes of the left lung. _______________ and

_______________.

5Figure 5-2A shows that, in the left lung, the upper lobe (U ) isseparated from the lower lobe (L) by the _______________(arrows). The major fissure (touched up for easy visibility) is[perpendicular/parallel] to the x-ray beam only in the lateralprojection. Figure 5-2B is a parasagittal CT reconstructionshowing the left major fissure (arrows).

6The oblique (major, vertical) fissure is not visible on the normalfrontal projection because (choose one):

(a) It is often anatomically absent.(b) It is not parallel to the x-ray beam.(c) It has the same roentgen density as lung tissue.

7In the right lung, the major (oblique) fissure separates the rightupper and middle lobes from the _______________. On the left,it separates the _______________ and _______________.

4

(a) left, because heart ison left

(b) upper, middle, lower(c) upper (lingula is part

of left upper lobe),lower

5

major (oblique) (vertical)fissureparallel

6

(b) It is not parallel tothe x-ray beam.

7

right lower lobeleft upper; left lowerlobes

The major fissure runs obliquely downward from about the level of the fifth thoracic vertebra to the diaphragm, where it ends at a point just short of theanterior chest wall (Figures 5-2A and 5-2B).

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FIGURE 5-4 A

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8The minor (horizontal) fissure separates the right middle lobefrom the [right upper/right lower] lobe. In an erect patient, theminor fissure is usually horizontal. It is [parallel/perpendicular]to the floor. This fissure should be visible in [the frontal/the lateral/both] view(s) (Figure 5-3B and Figures 5-4A and 5-4B).

9In many patients, the minor fissure is not perfectly horizontal.The anterior portion or the entire fissure slopes downward oris bowed, making it visible in the _______________ projectiononly. In others, the minor fissure is anatomically incompleteand not visible in one or both views.

8

right upperparallel

both

9

lateral

The fissure normally appears as a thin white line (2 layers of pleura surroundedby air) as in Figure 5-3A (arrowheads). There are two exceptions. If a lobe is con-solidated, the fissure appears as an edge, delineating that lobe. In Figure 5-3A,the lower fissure is a line (arrowheads), but the upper fissure is an edge(arrows) because the upper lobe is consolidated or airless. If pleural fluidenters a fissure, the fissure thickens. Note the thick major fissure (arrowheads)and normal minor fissure (arrow) in Figure 5-3B.

Just to confuse you a little, a small percentage of people have a left minor fissure between the lingula and the rest of the upper lobe. Watch for it.

FIGURE 5-4 B

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FIGURE 5-5

FIGURE 5-6 A

FIGURE 5-6 B

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10On the lateral film (Figure 5-5), the minor fissure starts posteriorlyat the _______________ fissure and ends on the _______________wall. This often helps you distinguish the right from the leftmajor fissure on the lateral view.

10

right major; anteriorchest

11Identify the following fissures on Figures 5-6A and 5-6B:

(a) I = _______________.(b) II = _______________.(c) III = _______________.

12Identify the following in Figures 5-6A and 5-6B:

(a) 1 and 2 = _______________.(b) 3 and 5 = _______________.(c) 3 and 4 = _______________.(d) 5 = _______________.(e) 6 = _______________.(f) 7 = _______________.

11(a) I = minor fissure(b) II = right major

fissure(c) III = left major fissure

12(a) 1 and 2 = upper lobes(b) 3 and 5 = right lower

and middle lobes(c) 3 and 4 = lower lobes(d) 5 = right middle lobe(e) 6 = lingula(f) 7 = left diaphragm

In the lateral view, it still may be difficult to tell the two major fissures apart.Here is a simple method: The left major fissure ends on the left diaphragm(Figure 5-5) (arrow). The left diaphragm is usually lower, usually has the stomachbubble immediately beneath it, and is not visible anteriorly because the bottomof the heart rests on it.

Note: On the frontal view (Figure 5-6A), the superior portions of the lower lobesrise to the level of the aortic arch (dotted lines). The upper portion of the lowerlobes (superior segment) is superior to the hilum.

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FIGURE 5-7 A

FIGURE 5-7 B

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13In Figures 5-7A and 5-7B, there is [alveolar consolidation/inter-stitial thickening] located in the _______________ lobe. Themajor fissure (arrow) forms the [superior/posterior] rightmiddle lobe boundary. The superior margin of the right middlelobe is the _______________ fissure (arrowhead).

13alveolar consolidationright middleposterior

minor

Clinical Pearl: Lobar pneumonia is usually bacterial in origin, caused byStreptococcus pneumoniae or Klebsiella. Mycoplasma and Legionella infectionsalso may cause lobar consolidation.

On radiographs, fissures are seen when parallel to the x-ray beam. On CT, struc-tures are best seen when perpendicular to the scan plane. The major fissures(arrows) are usually visible on axial CT images (Figure 5-8). The minor fissure isparallel to the scan plane and not visible.

FIGURE 5-8

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FIGURE 5-9 A

FIGURE 5-9 B

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14What about other fissures? There are three accessory fissuresseen occasionally in normal individuals. The azygos fissure(Figure 5-9A) is formed by an anomalous development of theazygos vein. The vein “migrates through” the medial rightupper lobe, dragging visceral and parietal pleura with it. Theazygos lobe is separated from the rest of the upper lobe by theazygos _______________ (arrow). Figure 5-9B shows a CT scan ofan azygos fissure and lobe.

15The azygos fissure separates a variable amount of the uppermedial region of the _______________ lobe. This portion of thelung is called the _______________ lobe. This information is of[great/little] clinical importance but interesting nonetheless.

14

fissure

15

right upperazygoslittle

Four doctors are duck hunting. As the ducks fly over, the internist says, “It lookslike a duck, smells like a duck, and quacks like a duck. I just need a second opin-ion.” By the time he is ready, the ducks are gone. The radiologist says, “It lookslike a duck, smells like a duck, and quacks like a duck. I need another view.” By the time he is ready, the ducks are gone. The surgeon just shoots and says,“Holy mackerel, what did I just shoot?” The pathologist says, “I think they wereducks, but I will need more tissue.”

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FIGURE 5-10 A

FIGURE 5-10 B

FIGURE 5-11

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16Figure 5-10A shows the position of another accessory fissure(arrows), the inferior accessory fissure. It separates the medialbasal segment of the _______________ lobe from the remainderof the lobe. Figure 5-11 shows the inferior accessory fissure(arrow).

17The azygos and inferior accessory fissures run in an anterior-posterior plane. They are visible in [the frontal/the lateral/both]view(s).

18The third accessory fissure is the superior accessory fissure. In Figures 5-10A and 5-10B, this fissure (arrowheads) is in thesame plane and posterior to the _______________ fissure. It should be visible in [the frontal/the lateral/both] view(s). A right superior accessory fissure superimposes on the minorfissure in the _______________ view.

19The superior accessory fissure divides the right _______________lobe into two portions: the four basal segments and the [superior/inferior/apical] segment.

16

right lower

17

the frontal

18

minorboth

frontal

19lowersuperior

Train yourself to look for the fissures on every chest image. They help to localizedisease in the lung. As we shall see, displacement of the fissures is the most reliablesign of lobar collapse.

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FIGURE 5-12 A

FIGURE 5-12 B

FIGURE 5-13 A

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REVIEW

IIdentify the fissures in Figures 5-12A and 5-12B:

(1) _______________(2) _______________ or _______________(3) _______________(4) _______________(5) _______________(6) _______________(7) _______________

IIThe only fissures visible on the frontal and lateral view are the_______________ fissure and the _______________ fissure. Why?_______________.

IIIAn unlucky seamstress gasped at the wrong moment. Carefullyscan Figures 5-13A and 5-13B, then answer the following questions:

A. What is the abnormality? _______________B. In what lobe is it located? _______________

I(1) azygos(2) minor; superior

accessory(3) inferior accessory(4) right major(5) minor(6) superior accessory(7) left major

IIminor; superior accessoryParallel to beam in both projections (bothhorizontal)

IIIA. aspirated a pinB. right lower lobe

FIGURE 5-13 B

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FIGURE 6-1

FIGURE 6-2

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87

SIX

THE SILHOUETTE SIGN

If part of the lung is radiodense (alveolar pattern, consolidated, water density, airless), itcan affect our ability to see adjacent structures. We can use these changes to help us detectand localize disease in the lung. This chapter discusses how disease in different lobesaffects the appearance of adjacent organs.

1There are four basic radiographic densities. In order of increasing radiodensity, they are gas, _______________,_______________, and _______________.

1

fatsoft tissue (water);metal (bone)

2

water (soft tissue)air

Figure 6-1 shows an upright test tube containing, from top down, air, oil (fat),water, and metal. Calcium is the prime example of metal density normally foundin the body. Note the sharp interface between each density. (Arrow = air/fatinterface; arrowhead = fat/water interface.)

In Figure 6-2, the heart, aorta, and diaphragms have sharp margins because theyare all water density, adjacent to air density. The inner stomach wall is visiblebecause air contacts the soft tissue wall. Converseley, the liver and rightdiaphragm are not seen separately because they are both of water density.

2Anatomic structures are recognized on an x-ray by their den-sity differences. These four basic densities keep the radiologistin business. Figure 6-2 is a normal chest x-ray. The heart and muscles are _______________ density. The lung and stomachbubble are _______________ density. The fat planes betweenthe muscles are barely visible. The “L” marker is metal (lead)density and the ribs are metal density.

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A B CFIGURE 6-3

FIGURE 6-4

FIGURE 6-5

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Six • The Silhouette Sign 89

3Let us reinforce this concept. Figure 6-3 shows three x-rays of amodel of the heart and aorta. In Figure 6-3A, the heart andascending aorta are in one empty box, and the descendingaorta is in a second empty box, behind the first. In Figure 6-3B,some water has been poured into the anterior box. The lowerheart borders have disappeared. The descending aorta is [visi-ble/not visible]. In Figure 6-3C, the water has been removed andplaced in the posterior box. The lower heart border is[visible/not visible]. The lower aortic border is not visiblebecause _______________.

3

visible

visibleaorta now contactswater, rather than air

4air

soft tissue (water)soft tissue

5A, B, C

similar

In Figure 6-4, the left diaphragm is visible, but the right is not because the adjacentright lower lobe is consolidated (airless)—the silhouette sign. The right heartborder, still in contact with aerated right middle lobe, is visible. The left heartborder is normal.

The heart, aorta, and blood—as well as the liver, spleen, and muscles—all aresoft tissue density. So is diseased airless lung. Two substances of the same den-sity, in direct contact, cannot be differentiated from each other on an x-ray. Thisphenomenon, the loss of the normal radiographic silhouette (contour), is calledthe silhouette sign.

4In Figure 6-4, the trachea, which is _______________ density,can be differentiated from the mediastinum, which is_______________ density. The liver and diaphragm cannot beseparated because both are _______________ density and indirect contact.

5In Figure 6-5, which structures are visible?

A. Right diaphragmB. Right heartC. Left diaphragmD. Left heart

An interface is not visible when two areas of [similar/different] radiodensity touch.

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FIGURE 6-6 A

FIGURE 6-6 B

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6Now that you know what the silhouette sign is, what are yougoing to do with it? The silhouette sign helps diagnose andlocalize lung disease. If you know the position of intrathoracicstructures, you can precisely localize the lung disease. Theheart and ascending aorta are [anterior/posterior] structures.Conversely, the descending aorta is a(n) [anterior/posterior]structure. The aortic arch crosses the middle mediastinum from_______________ on the right to _______________ on the left.

6

anteriorposterior

anterior; posterior

Figure 6-6A is a lateral view of the chest with an atherosclerotic (calcified) aorticwall. The heart and ascending aorta (A) are anterior, and the descending aorta(D) is posterior. Figure 6-6B is a CT scan taken through the aortic arch as itpasses from right anterior to left posterior. In Figure 6-6C, the ascending aorta (A) is anterior, and the descending aorta (D) is posterior. (P = pulmonary artery.)

FIGURE 6-6 C

7The diaphragms contact the _______________ surface of thelung. The _______________ lobes contact the diaphragm.

8There is even a “normal” silhouette sign on the lateral chest x-ray. In Figure 6-6A, we see two diaphragms posteriorly, butonly one anteriorly. The heart sits on the [right/left] diaphragm,obscuring the anterior diaphragm. How can this be useful?_______________.

7inferiorlower

8

left

It helps to distinguish theleft and right diaphragmson the lateral

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FIGURE 6-7

FIGURE 6-8 A

FIGURE 6-8 B

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9Let’s wrap this up. State the anterior or posterior location ofeach of the following:

(a) right heart border = _______________(b) descending aorta = ________________(c) left heart border = _________________(d) ascending aorta = _________________(e) aortic knob (arch) = _______________

10Each lobe produces a characteristic silhouette sign of which wecan take advantage. The right middle lobe and lingula lie inanatomic contact with the _______________. All are [anterior/posterior] structures. In the chest x-ray in Figure 6-7, the heartborder is not visible on the _______________. There must beconsolidation (water density) in the _______________ lobe.

9

(a) anterior(b) posterior(c) anterior(d) anterior(e) mid posterior

10

heartanteriorright (silhouette sign)right middle

11visibleDiaphragms are adjacentto aerated lower lobes

12

posterior; major

diaphragms

In Figure 6-8A, there is a silhouette sign of the left heart border. In Figure 6-8B,the CT scan shows the consolidated lingula adjacent to the left heart.

11In Figures 6-7 and 6-8A, the diaphragms are [visible/invisible].Why? _______________.

12Let’s look at the lower lobes. They sit inferior and[anterior/posterior] to the [major/minor] fissure. They are notin anatomic contact with the heart borders, which are anteriorstructures. Instead, the lower lobes sit on the _______________,which are inferior structures.

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FIGURE 6-9

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13If only the right diaphragm is obscured, the disease is in the_______________. If the right heart border and the diaphragmare obscured, there is consolidation of the _______________ and_______________.

14Airspace disease in either lower lobe overlaps the hilum andthe heart border, but does not obscure their silhouette becausethey are _______________.

15The descending aorta is not visible when there is_______________ consolidation, as in Figure 6-9. Compare withFigures 6-7 and 6-8.

13

right lower loberight middle loberight lower lobe

14

not in direct contact

15

left lower lobe

Figure 6-9 shows bilateral disease. On the right, there is a silhouette sign of theright heart and the diaphragm, indicating right middle and lower lobe disease.The left diaphragm is not visible because of a left lower lobe consolidation. Theleft heart border is sharp; the lingula is aerated.

Clinical Pearl: In the ICU, left lower lobe atelectasis or pneumonia is frequent.Check the diaphragm and descending aorta through the heart on every film fora silhouette sign.

Woman in labor: “Can’t. Shouldn’t. Didn’t. Won’t.”Husband: “Doctor, what’s wrong with my wife?”Obstetrician: “Contractions!”

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FIGURE 6-10

FIGURE 6-11

FIGURE 6-12

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16The upper right heart border and [ascending/descending]aorta are anterior structures on the right. The descending aortais _______________ on the left. The trachea and the aortic knobare located in the [anterior/mid/posterior] thorax.

17The right upper lobe occupies the anterior and midthoraxabove the _______________ fissure and anterior to the_______________ fissure. Right upper lobe consolidation causesa silhouette sign of the [ascending/descending] aorta and theright tracheal lung interface. Figure 6-10 shows right upper lobeconsolidation obscuring the upper mediastinum and ascendingaorta.

18The left upper lobe occupies the anterior and mid upper thorax.Left upper lobe consolidation (upper division) obliterates the_______________ atrium, the aortic knob, and the _______________and _______________ mediastinum. Figure 6-11 shows the silhouette sign in left upper lobe consolidation.

19You have seen that a silhouette sign helps localize disease.Sometimes it actually helps detect disease. Study Figure 6-12carefully. There are two subtle silhouette signs indicating dis-ease in the _______________ and _______________. Note: Bothheart borders are indistinct. You would need a lateral film or CTscan to confirm.

16ascending

posteriormid

17

minormajorascending

18

left; anteriormiddle

19

right middle lobe; lingula

A positive silhouette sign is very helpful. A negative silhouette sign does notensure that a given lobe is disease-free because it may be partially aerated andnot cause a silhouette sign. Be careful!

You have learned that the silhouette sign applies to radiodense lung lesions. It also applies to soft tissue density mediastinal and pleural lesions. It applieswhenever two structures of the same density are in contact.

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FIGURE 6-13

FIGURE 6-14

FIGURE 6-15

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20Figure 6-13 shows a mediastinal mass obscuring the ascendingaorta and the tracheal-lung interface. This large mass must bein the _______________ and _______________ mediastinum.What does it do to the tracheal width? _______________.

21We learned there is even a normal silhouette sign on the lateral radiograph that we can use to our advantage. The heartsits predominantly on the [anterior/posterior] [left/right]diaphragm. Both structures are of _______________density. The[anterior/posterior] part of the left diaphragm is usually not visible. On the lateral, the right diaphragm is visible throughthe heart because _______________. This helps distinguish theleft from the right diaphragm on the lateral.

20

anterior; middleIt narrows the trachealwidth

21

anterior; leftsoft tissue (water)anterior

it contacts aerated lung

Now that everything is clear—here come the exceptions. (1) The silhouette signmay be misleading on an underpenetrated radiograph (a film that is too light).Figure 6-14 is an underpenetrated film. The left diaphragm and descending aortaare not visible through the heart. If you cannot see the spine through the heart, thefilm is underpenetrated, and a silhouette sign may be misleading. (2) Sometimesthe right heart border overlies the spine and does not protrude into the rightlung. The density of the spine hides the lung-heart interface. You can’t hit ’em ifyou can’t see ’em.

Figure 6-15 shows two silhouette signs of the left diaphragm. The anterior one isdue to the heart, and the posterior one is due to pneumonia (P) in the left lowerlobe. Only the middle third of the left diaphragm is visible (*). The entire rightdiaphragm is visible.

The silhouette sign is nearly always an abnormal finding. It is usually due tolung disease. It may be present even when you cannot see the disease causing it.On every chest film you see from now on, look for the silhouette sign.

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FIGURE 6-16

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REVIEW

IFrom the following descriptions of PA films, localize the lesion.

(a) Lung consolidation obscures the left heart border:_______________

(b) Lung consolidation obliterates the aortic knob:_______________

(c) A right lung base pneumonia fails to obliterate the heart:_______________

(d) A right lung base pneumonia obliterates the heart:_______________

(e) A pneumonia obscures the descending aorta:_______________

IILet’s review exceptions or false (+) silhouette signs.

A. A pseudosilhouette sign of the diaphragm may occur onan [over/under]penetrated radiograph. The radiographis too [light/dark].

B. If the heart is positioned slightly to the left, the rightheart border may not be seen because _______________.

C. On the lateral radiograph, the heart normally obscuresthe _______________.

IIIIn Figure 6-16, the patient has pneumococcal pneumonia.Without a lateral, determine which lobe(s) is(are) consolidated._______________How did you decide? _______________.

I

(a) lingula

(b) left upper lobe

(c) right lower lobe(probably)

(d) right middle lobe

(e) left lower lobe

IIA. under; light

B. it overlaps the spine

C. anterior leftdiaphragm

IIIright middle lobe, rightlower lobe, lingula

Right and left heart sil-houette signs and rightdiaphragm silhouettesign. Left diaphragm isvisible

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FIGURE 7-1 A

FIGURE 7-1 BFIGURE 7-1 C

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103

SEVEN

THE AIRBRONCHOGRAM SIGN

On the normal chest x-ray, we see air in the trachea and proximal bronchi because they aresurrounded by the soft tissue (water density) of the mediastinum. In the lungs, however,the bronchi are not visible. The only branching structures visible in the lungs are the pulmonary vessels (water density) surrounded by air.

1The linear markings seen in the lungs are basically blood vessels,which are __________ density. Because bronchi have very thinwalls, contain air, and are surrounded by air-filled alveoli, theintraparenchymal bronchi [are/are not] visible on a normalchest x-ray.

1

water (soft tissue)

are not

In Figure 7-1A, the branching pulmonary vessels are visible in the lung. The tracheaand proximal main bronchi (arrows) are surrounded by mediastinal soft tissueand are visible. The peripheral bronchi are not visible. On CT, the bronchi arenormally visible through much of the lung. In Figure 7-1B, right lower lobebronchi appear tubular (in plane) and left lower lobe bronchi appear circular(perpendicular to plane). Figure 7-1C, a coronal CT reconstruction, shows thedistal trachea, carina, and intraparenchymal bronchi (in plane).

2To visualize the bronchi, we used to instill an opaque material(iodinated oil) into the bronchial lumen. The “positive” contrastbronchogram is seldom performed now because patients[loved/hated] having thick oily goop dumped into their bronchi.

2

hated

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FIGURE 7-2 A

FIGURE 7-2 B

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Seven • The Air Bronchogram Sign 105

3Do we ever see normal bronchi on a chest x-ray? Sure we do!When the lung is consolidated and the bronchi contain air, thedense lung delineates the air-filled bronchi. Visualization of airin the intrapulmonary bronchi on a chest roentgenogram iscalled the air bronchogram sign. The presence of an air bron-chogram indicates [normal/abnormal] lung.

3

abnormal

Figure 7-2A shows a bronchogram with iodinated contrast medium filling normalmedial bronchi and dilated lateral bronchi (bronchiectasis). CT has replacedbronchography. In a different patient, Figure 7-2B shows multiple dilated bronchiin cross section on the left and relatively normal bronchi on the right. Figure 7-2Cis a coronal CT scan that shows the left lower lobe bronchiectasis.

FIGURE 7-2 C

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FIGURE 7-4 FIGURE 7-5

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4Figure 7-3A simulates the normal lung with straws. Straw V(vessel) contains water, and straw B (bronchus) contains air.They are x-rayed in air. Straw _____________ is easily seen.Straw _________ is much less visible because of ____________.

5Figure 7-3B portrays a diseased (consolidated) lung; the strawsare immersed in water. Straw B is now ________, the ________sign. Straw V now disappears, the ________ sign. If you missedthis, review questions 1-5.

4

VB; air inside and outside the thin-walledstraw

5

visible; air bronchogramsilhouette

Figure 7-4 is a scout view of a patient with left lower lobe pneumonia. The bronchiappear as branching black tubes in the consolidated lung behind the heart. In Figure 7-5, the CT scan shows a right middle lobe air bronchogram. Mild consolidation elsewhere does not give an air bronchogram.

6 6“Doctors without borders”

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7Soft tissue and air density are involved in the air bronchogramand silhouette sign. If an air-filled bronchus is to be seen, it must be surrounded by ____________ density. Conversely, if a pulmonary vessel is to be seen, it must be surrounded by _________. Not seeing the lung vessels is a variation of thesilhouette sign.

7

soft tissue (water)(increased)air

Figure 7-6 is a radiograph of a patient with generalized alveolar consolidation.Many bronchi are visible, but the pulmonary vessels are not. Arrows indicate airbronchograms in both upper lobes and the right lower lobe.

8What good is the air bronchogram sign? Well, for one thing,bronchi are pulmonary structures; visualization of the bronchi(air bronchogram) indicates a ____________ lesion, rather thana pleural or mediastinal lesion. It means that the bronchi contain ___________ and the adjacent lung is _____________.

8

pulmonary

air; consolidated (radio-dense)

Figure 7-7 shows a dense area of consolidation with air-filled bronchi (arrows).Because there is an air bronchogram sign, we know the lesion is in the lung and not in the mediastinum. Individual vessels are not visible because they aresurrounded by water density.

9The air bronchogram may be seen in pneumonia, pulmonaryedema, pulmonary infarction, and certain chronic lung lesions.As long as the bronchi are __________ and the surrounding lungis radiopaque (water density), a(n) _______________ sign will bepresent.

9

air-filledair bronchogram

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FIGURE 7-8

FIGURE 7-9

FIGURE 7-10

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10Do we always see an air bronchogram with pulmonary parenchy-mal consolidation? “Always,” of course, is _________ the answerin medicine. If a bronchus is obstructed or filled with secretions,a pulmonary lesion [would/would not] show an air bronchogram.

10

never

would not

Patchy peripheral lung consolidation or interstitial disease usually does not causeenough opacity to produce an air bronchogram. Conditions that hyperinflate thelungs do not cause air bronchograms.

11A. In pneumonia, if the bronchi are filled with secretions,

there [would/would not] be an air bronchogram withinthe lesion.

B. If a cancer obstructs a bronchus, an air bronchogram[would/ would not] be visible.

C. Interstitial fibrosis [would/would not] cause an air bronchogram.

D. Asthma [would/would not] cause an air bronchogram.

11

A. would not

B. would notC. would not

D. would not

In Figure 7-8, there is no air bronchogram in the collapsed right upper lobe becausethe bronchi are full of mucous plugs. Compare with Figure 7-7. In Figure 7-9, thereis no air bronchogram in the consolidated lingula because a tumor obstructsthe proximal bronchus, and the bronchial air has been replaced by secretionsor resorbed.

12The presence of an air bronchogram indicates a ___________lesion. The absence of an air bronchogram indicates the lesion may be [pulmonary/extrapulmonary/either pulmonary or extrapulmonary].

12lung

either pulmonary orextrapulmonary

Clinical Pearl: The heart shadow often obscures left lower lobe disease on an APor PA radiograph. Sometimes an air bronchogram seen through the cardiacshadow is the most definitive sign of left lower lobe consolidation. In Figure 7-10,air bronchograms (arrows) are visible through the density of the heart. There isalso a silhouette sign of the medial diaphragm.

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FIGURE 7-11

FIGURE 7-12

FIGURE 7-13

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13So it’s easy! Remember, consolidated lobes may not show an airbronchogram if:

A. The bronchi are full of secretions [true/false].B. There is an aspirated foreign body in the bronchus

[true/false].C. There is not complete lung consolidation [true/false].D. The patient has only emphysema [true/false].

13

A. trueB. true

C. trueD. true

Clinical Pearl: An air bronchogram indicates open airways, strong evidence that the lung disease is not due to an obstructing tumor in a smoker.

14Are there any other uses of the air bronchogram? If you see air-filled bronchi that are very crowded together, this is evidenceof lung [overexpansion/collapse]. The crowded air bronchogramssuggest this is [obstructive/nonobstructive] atelectasis. InFigure 7-6, the bronchi are normally spaced, whereas in Figure 7-7, they are crowded.

15Several diseases may cause bronchiectasis. Instead of tapering,the bronchi ____________, as they course peripherally.

14

collapse (atelectasis)nonobstructive

15

widen (dilate)

Bronchiectasis is difficult to diagnose and illustrate on an x-ray. Figure 7-11shows dilated bronchi (arrows) at the lung base. Figure 7-12 shows dilated, thick-ened bronchi. Bronchi running in the axial plane are tubular (straight arrows),and bronchi running across (perpendicular to) the axial plane are circular(curved arrow). Figure 7-13 shows dilated bronchi completely filled with secre-tions in plane (straight arrows) and in cross section (curved arrow).

Anagram: Rearrange the letters in DORMITORY to form two words that betterdefine it (answer on next page).

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REVIEW

IAny tubular structure (bronchus, vessel), viewed longitudinally,looks _____________. The same structure seen on end appears__________. The inside of the bronchus is radiolucent because__________, whereas the inside of a vessel is ____________because it contains blood.

IIWhich of the following conditions may show an air bronchogram?

(a) tuberculosis(b) empyema(c) emphysema(d) mediastinal bronchogenic cyst(e) bacterial pneumonia(f) adult respiratory distress syndrome (ARDS)

IIIA. Bronchi crowded together indicate _______________.B. Dilated bronchi indicate ______________.C. If an air bronchogram is visible, an endobronchial tumor

is ________________.

IVFigures 7-14A and 7-14B are two postoperative patients withshortness of breath.

A. Both show consolidation of the ____________ lobe.B. The sharp demarcation between normal and abnormal

lung is the ______________.C. Air is seen in the bronchi of [Figure 7-14A/Figure 7-14B].

This is the ______________ sign.D. There is no air bronchogram sign in Figure 7-14B because

of _______________.E. Which patient would benefit little from endobronchial

suction or bronchoscopy? ______________

I

linear, tubularcircularit contains air;radiodense or radiopaque(water density)

II

(a) tuberculosis

(e) bacterial pneumonia(f) ARDS

IIIA. collapse, atelectasisB. bronchiectasisC. very unlikely

IV

A. right lowerB. major fissure

C. Figure 7-14A; airbronchogram

D. mucus in the bronchi

E. Figure 7-14A (nomucus to suction)

Anagram: DORMITORY = Dirty Room

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FIGURE 8-1

a

b

c

FIGURE 8-2 A

d

e

FIGURE 8-2 B

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117

EIGHT

SIGNS OF LUNG ANDLOBAR COLLAPSE

Detecting signs of collapse within the lung is important in the diagnosis of lung disease. For us, it is also a good way to reinforce the anatomy. In general, the term “collapse” is usedto describe marked decreased volume of a lung, a lobe, or a segment. “Atelectasis” or “volume loss” is often used to describe less severe changes. The terms are fuzzy andinterchangeable (hard to believe). First, let’s look at the patterns of collapse on x-ray and CTand then possible mechanisms.

1When a whole lung collapses, the volume diminishes, and adjacentstructures move toward that lung. In Figure 8-1, the left lung is consolidated and collapsed. The trachea is [midline/left of midline/right of midline]. The heart has disappeared because[it shifted left/it shifted right/there is Nocardia]. If the diaphragmwere visible, it would be [elevated/depressed/in a normal position].

2The fissures that divide the lobes are formed by [two parietalpleural layers/two visceral pleural layers/one visceral pleurallayer/one parietal pleural layer].

3Because fissures demarcate the boundaries of the lobes, thebest sign of lobar collapse is shift of the fissures. Look atFigures 8-2A and 8-2B and decide which lobe has collapsed.

(a) ________________________(b) ________________________(c) ________________________(d) ________________________(e) ________________________

1

left of midline

it shifted leftelevated

2two visceral pleurallayers

3

(a) right upper lobe(b) right middle lobe(c) right lower lobe(d) left upper lobe(e) left lower lobe

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FIGURE 8-3 B

FIGURE 8-3 A


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Eight • Signs of Lung and Lobar Collapse 119

4Let’s try this for real. In Figure 8-3, there is consolidation of the ____________ lobe. The sharp inferior margin is caused bythe ____________. It is [elevated/depressed/normal] in position.The accompanying CT scan shows collapse of the right upperlobe, and the arrow points to an endobronchial tumor obstructingthe right upper lobe bronchus.

5In Figure 8-4A, the position of the minor fissure is [inferior/superior/unchanged]. The position of the major fissure is [anterior/posterior/unchanged]. There is a triangular densityover the heart. This is the collapsed __________ lobe.In Figure 8-4B, there is a silhouette sign of the _________, causedby ___________.

6The diagnosis of right middle lobe collapse is often easier on the [frontal/lateral] view. Changes on the frontal radiographare often subtle. A triangular density, similar to right middlelobe collapse, may be present on the lateral, with collapse of the ______________.

4

right upperminor fissure; elevated

5inferior

anteriorright middleright heart border; right middle lobe consolidation

6

lateral

lingula

Figure 8-5 shows collapse of two lobes on the right. The minor fissure is elevated.The right upper lobe is partially collapsed. There is a silhouette sign of the rightdiaphragm, and the heart has moved to the right, indicating right lower lobe collapse. The right middle lobe remains aerated. We see the undersurface of the minor fissure and the right heart border because the right middle lobe is aerated.

FIGURE 8-5

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FIGURE 8-6 A

FIGURE 8-6 B

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7In Figure 8-6A, let’s start with the lateral. The arrows pointto the [minor fissure/major fissure/azygos fissure]. The fissureis displaced [anteriorly/posteriorly/unchanged]. On the frontalview (Figure 8-6B), there is a mass in the left hilum, and the leftdiaphragm is ________________. This is a case of total collapseof the ______________________.

7

major fissureanteriorly

elevatedleft upper lobe (includ-ing lingula)

The left upper lobe and lingula share a common bronchus. It is common for anendobronchial lesion (tumor, foreign body, mucus) to obstruct them together. InFigure 8-6A, the upper arrow is at the level of the upper lobe, and the lowerarrow is at the level of the lingula.

8Similarly, the bronchus intermedius on the right supplies the right _________ and _________ lobes. These two lobes oftencollapse together. Figure 8-7 shows dense consolidation at theright base. The minor fissure is [elevated/depressed/normal].There are silhouette signs of the ___________ and __________.The right [upper/middle/lower] lobe(s) is(are) collapsed.

9The [left upper lobe/lingula/left lower lobe] share a commonbronchus. On the right, the middle and lower lobes share acommon bronchus, called the _____________. A complete obstruc-tion of either bronchus causes collapse of [one/two/three] lobes.

8

middle; lower

depresseddiaphragm; right heart;middle and lower

9left upper lobe and lingulabronchus intermediustwo

Movement of the fissures is the most reliable sign of lobar collapse. Crowding of pulmonary vessels or bronchi and movement of parenchymal landmarks (e.g., nodules, granulomas, surgical clips) also can indicate volume loss.

FIGURE 8-7

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FIGURE 8-8


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10If a lobe or segment is atelectatic, but still contains some air,the vascular markings would be visible, but in a [smaller/larger]volume. If the lung is consolidated, the air bronchogram signmight show us the bronchi. In either case, the vessels or bronchiwould appear [further apart/crowded together].

10

smaller

crowded together

Figure 8-8 shows crowded air bronchograms in left lower lobe collapse (arrows).The collapsed lung is difficult to see behind the heart. There is a silhouette signof the left diaphragm.

11In Figure 8-9A, there is a nodule in the right upper lobe. InFigure 8-9B, after a needle biopsy, the nodule position is[unchanged/more lateral/more medial]. The nodule has movedbecause the lung volume is [static/increased/decreased]. Thenodule moved medially because there is now air in the pleuralspace (pneumothorax) (arrow). (Yes, I did the biopsy.) Moving“marker” structures may indicate volume loss.

12The best and most frequent sign of lobar collapse is _________.Two less frequent signs of lung collapse are _______________and ________________.

11

more medialdecreased

12fissure movementcrowded bronchi andvesselsmoving marker structures

The above-mentioned signs are direct signs of lobar collapse. There are severalless specific signs, such as shift of adjacent structures and change in lung density.

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FIGURE 8-10

FIGURE 8-11

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13Hilar depression indicates collapse of a(n) [upper/lower] lobe.Hilar elevation indicates collapse of a(n) [upper/lower] lobe.Middle lobe or ____________ atelectasis usually does not shiftthe hilum. Hilar shift is a reliable indirect sign of atelectasis.

13lowerupperlingular

To appreciate hilar displacement, one must know the relative positions of thenormal hila. In more than 97% of individuals, the left hilum (L) is slightly higherthan the right (R) (Figure 8-10). In the remaining 3%, the hila are at the samelevel. Figures are based on 1000 normal chest x-rays studied by Dr. Felson whenhe had nothing better to do (World War II noncombat overseas assignment, wifein the U.S., and pre-television).

14The indirect signs rely on shift of structures [toward/awayfrom] the collapsed lung. For instance, in lobar atelectasis, thediaphragm is often [elevated/depressed]. By the way, whichdiaphragm is usually higher? ___________.Similarly, mediastinal structures may shift. With upper lobe collapse, the trachea shifts toward the lesion (see Figure 8-5).With [lower/upper] lobe collapse, the heart may shift towardthe side of collapse (see Figure 8-5).

14toward

elevatedthe right, by a few cen-timeters

lower

Volume loss usually changes the density of the lung. The airless, atelectatic lungis more radiopaque, and adjacent lobes may hyperinflate to fill the void. This“compensatory hyperinflation” causes the aerated lobe to be more radiolucent.

15In Figure 8-11:

A. The left upper lobe is ____________ radiolucent than theright upper lobe.

B. The left hilum is [higher than/lower than/the same levelas] the right.

C. The ______________ diaphragm is elevated.D. There is an air bronchogram in the _______________.E. Diagnosis: __________________

15

A. more

B. the same as

C. leftD. left lower lobeE. left lower lobe

collapse

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FIGURE 8-12 A

FIGURE 8-12 B

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16If the airway is obstructed, air distal to the obstruction is___________. Obstruction may be central (i.e., a lesion blockinga main, lobar, or segmental bronchus) or peripheral (e.g.,multiple small mucous plugs, blood clots) in small bronchi. Air distal to any obstruction is resorbed, and that portion of the lung _____________.

17When the obstruction is central, it may be due to a lesion in thebronchus causing intrinsic obstruction or an external lesioncompressing the bronchus, causing extrinsic obstruction.

(1) In Figure 8-12A, the right upper lobe collapse (C) is dueto _________, causing [intrinsic/extrinsic] obstruction.

(2) In Figure 8-12B, there is bronchial narrowing that is due to [intrinsic/extrinsic] obstruction.

16

resorbed

collapses (becomesatelectatic)

17

(1) endobronchialobstruction; intrinsic

(2) extrinsic (tumoraround bronchus)

The natural tendency of the lung is to collapse. Various physiologic mechanismskeep the lung expanded. When one or more fails, the lung tends to lose volume.There are five basic mechanisms that cause volume loss: (1) resorption of air asa result of obstruction of a bronchus; (2) relaxation of the lung as a result of airor fluid in the pleural space; (3) scarring, causing lung contraction; (4) decreasedsurfactant reducing lung distensibility (adhesive atelectasis); and (5) hypoventila-tion as a result of central nervous system depression or pain.

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FIGURE 8-13 A

FIGURE 8-13 B

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18Figures 8-13A and 8-13B show postoperative atelectasis.

(1) Central obstructive atelectasis is seen in Figure 8- ______.How did you decide? ___________. The most likely causeis _________.

(2) In Figure 8-13B, there is postoperative collapse of____________. Air bronchograms are [present/absent].Collapse must be due to peripheral mucous plugging or hypoventilation.

19Figure 8-14 is a coronal CT reconstruction showing a large[pneumothorax/hydrothorax]. The central lucency (C) is thecollapsed right lung. The mechanism is known as ____________or __________ atelectasis. Fluid in the pleural space or ________in the pleural space causes this type of atelectasis.

18

(1) 13A; no air bron-chogram; mucus inairway

(2) both lower lobes;present

19

hydrothoraxpassive; relaxation; air

Clinical Pearl: In children, central obstruction is often due to a mucous plug oran aspirated foreign body. In adults younger than 40 years old, it is usually dueto a mucous plug, a foreign body, or a low-grade endobronchial tumor (adenoma,carcinoid). In adults older than age 40, bronchogenic carcinoma is a frequentcause of postobstructive collapse.

FIGURE 8-14

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FIGURE 8-15

FIGURE 8-16

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20Pulmonary fibrosis, either local (e.g., tuberculous scarring,radiation fibrosis) or generalized (e.g., silicosis, sarcoidosis),results in diminution in volume. In Figure 8-15, the [right/left]hilum is [elevated/depressed/normal]. The minor tissue is elevated (arrows). The trachea is ________. These signs indi-cate collapse of the ____________ lobe. This is termed___________ atelectasis.

21Surfactant diminishes surface tension in the alveoli, making iteasier to inflate the lung. Diminished surfactant promotesvolume loss. This is termed _____________ atelectasis. Name adisease or condition that causes adhesive atelectasis: ________.

20

rightelevatedshifted rightright upper; cicatriza-tion (scarring)

21adhesive; respiratorydistress syndrome ofthe newborn, adult respiratory distress syn-drome (ARDS), uremia,cardiac bypass surgery

Clinical Pearl: Hypoventilation atelectasis is frequent after general anesthesiaor heavy sedation. It most often involves the lung base.

22State the mechanism of atelectasis for the following conditions:

(a) An aspirated peanut causes [intrinsic/extrinsic] obstruc-tion, an example of [central/peripheral] resorptiveatelectasis.

(b) A sedative overdose causes _________ atelectasis.(c) A hemothorax causes _________ atelectasis.(d) Radiation fibrosis causes __________ atelectasis.(e) Adenopathy from lymphoma causes [intrinsic/extrinsic]

bronchial compression leading to [central/peripheral]resorptive atelectasis.

Atelectasis also can occur at the segmental level or in randomsmall areas of the lung parenchyma. This usually presents as alinear band of dense lung, often referred to as plate or bandlikeatelectasis. Figure 8-16 shows bandlike atelectasis at the lungbase caused by hypoventilation.

22

(a) intrinsic; central

(b) hypoventilation(c) relaxation (passive)(d) cicatricial

(e) extrinsic; central

Anagram: Twelve plus one = ___________________.

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FIGURE 8-17 A

FIGURE 8-17 B

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REVIEW

IFigure 8-17A is an x-ray of a patient 8 hours after general surgery. This is a chance for you to pull together what you havelearned in the last several chapters.

A. Which lobes are collapsed? _________ and __________.B. Direct signs? ___________.C. Indirect signs? __________.D. Air bronchograms are [present/absent], indicating

___________.E. Silhouette sign—where? ___________.

IIFigure 8-17B is an x-ray of another patient, several hours aftersurgery.

A. Which lobes are collapsed? ___________ and __________.B. Direct signs? _____________.C. Indirect signs? ____________.D. Air bronchograms are [present/absent].E. Silhouette sign—where? ______________ and __________.

IA. right middle lobe;

right lower lobeB. minor fissure downC. mediastinal shift,

upper lobe hyperin-flated, right middlelobe and right lowerlobe radiopaque

D. absent; mucus inmajor bronchi

E. diaphragm, rightheart

IIA. left upper lobe;

lingulaB. noneC. elevated diaphragm,

heart shifted left,increased density

D. absentE. left heart border;

mediastinum

Anagram: Twelve plus one = eleven plus two.

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FIGURE 9-1 A

FIGURE 9-1 B

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135

NINE

PATTERNS OF LUNGDISEASE

We have already seen how disease can consolidate or collapse a segment or lobe. We nowlook at other patterns of diffuse and focal lung disease. The lung reacts to disease in alimited number of ways. The interstitium can thicken or thin, and the alveoli can fill with fluid or extra air. These changes may be focal or diffuse. They may be acute or chronic.This leads to 16 possible combinations (interstitium = thick/thin) × (alveoli = fluid/air)× (location = focal/diffuse) × (time = acute/chronic). Relax. We concentrate only on the mostcommon combinations. These four basic variables help us analyze the chest x-ray and forma differential diagnosis.

1First, a brief review. For each chest radiograph, we ask, “Are There Many Lung Lesions?”

A = _____________T = _____________M = _____________L = _____________L = _____________

Review the search patterns outlined in Chapter 3, if necessary.

2Conceptually, the lung has two components, the supportingstructures (e.g., arteries, veins, bronchi), known as the_____________, and the air sacs known as the _____________. Air sacs form acini, and several acini form a _____________.Review Figures 9-1A and 9-1B.

3On a normal chest x-ray (Figure 9-1A), the “interstitium” isbasically the branching _____________. As they branch, theydisappear peripherally because they are _____________.

1

A = abdomenT = thorax (bones and

soft tissue)M = mediastinumL = lung—unilateralL = lung—bilateral

2

interstitium; alveolisecondary pulmonarylobule

3

pulmonary vesselsbeyond the resolutionof the x-ray

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FIGURE 9-2 A

FIGURE 9-3 A

FIGURE 9-3 B

FIGURE 9-2 C

FIGURE 9-2 B

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Nine • Patterns of Lung Disease 137

4The normal air-filled alveoli (air sacs) are too small to resolve,but in total they appear uniformly [radiolucent/radiodense].

5Match the following descriptions with the CT patterns shown inFigures 9-3A and 9-3B.

(1) normal = _____________(2) alveolar filling disease = _____________(3) linear (reticular) interstitial thickening = _____________(4) nodular interstitial thickening = _____________

4

radiolucent black

5

(1) B(2) C(3) A(4) D

Most lung diseases result in increased radiodensity of the lung. If the intersti-tium thickens, it can be seen more peripherally on the x-ray or CT scan. If theinterstitial thickening is generalized, the pattern is linear (reticular) (Figure 9-2A).If the thickening is discrete, it forms multiple nodules (Figure 9-2B). If the alveolifill with fluid, the fluid-filled area becomes radiodense, and the interstitium isenveloped in the dense white lung and is not visible (Figure 9-2C).

In your mind’s eye (whatever that is), fuse the patterns in Figure 9-2 with thosein Figure 9-3.

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FIGURE 9-4 C

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6Match the patterns listed with the patterns illustrated inFigures 9-4A, 9-4B, and 9-4C.

(1) alveolar filling disease = _____________(2) reticular (linear) interstitial thickening = _____________(3) nodular interstitial thickening = _____________

7Let us start to look at the specific patterns. In interstitial lungdisease, if the peribronchovascular tissue thickens, the vesselsor “markings” appear [more/less] prominent. At the same time,the alveoli are still _____________. The basic appearance is oneof aerated lung but with too many “markings.”

8Figures 9-4A and 9-4B show prominent interstitial markings,which may be in one area of the lung (focal) or generalized(diffuse).

1. In Figure 9-4A, the dominant pattern is [linear/nodular]and [diffuse/focal].

2. In Figure 9-4B, the dominant pattern is [linear/nodular]and [diffuse/focal].

9In general, acute and chronic interstitial lung diseases looksimilar. If the markings are hazy (ill defined) and not distorted(i.e., normal branching pattern), the disease is probably[acute/chronic]. If the lung markings are sharp (well defined)and distorted (i.e., angular, irregular, bowed), the disease isprobably [acute/chronic].

6

(1) Figure 9-4C(2) Figure 9-4A(3) Figure 9-4B

7

moreaerated

8

1. linearfocal

2. nodulardiffuse

9

acute

chronic

Clinical Pearl: Most diffuse interstitial lung disease is chronic and usually dueto fibrosis. Acute diffuse interstitial lung disease is usually due to pulmonaryedema and viral/mycoplasmal pneumonia.

Clinical Pearl: The most reliable method of distinguishing acute from chronic isby viewing past films or, heaven forbid, taking a history. Neither is cheating. It is synthesizing information to arrive at the best possible answer for the patient.

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FIGURE 9-5 A

FIGURE 9-6 A

FIGURE 9-5 B

FIGURE 9-6 B

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10Figure 9-5A shows diffuse interstitial lung disease. The “intersti-tial” markings are [increased/decreased], whereas the alveoliare [aerated/airless]. It is chronic because the markings are[distorted/not distorted] and [distinct/indistinct]. In Figure 9-5B,the CT scan shows distorted and sharp interstitium and aeratedlung.

11Match the patterns with the likely cause:

Pattern1. Interstitial markings are thickened = _____________2. Interstitial markings are very sharp = _____________3. Interstitial markings are indistinct = _____________4. Interstitial markings are distorted = _____________5. Interstitial markings change over several days = ________Likely Cause(A) acute(B) chronic(C) acute or chronic

10

increasedaerateddistorted; distinct

11

1. C2. B3. A4. B5. A

Another form of fibrosis is “honeycombing.” The fibrosis forms multiple smallcysts, often stacked up one on another, just beneath the pleura. Figures 9-6A and9-6B show an x-ray and CT scan with honeycombing.

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FIGURE 9-7

FIGURE 9-8

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12In Figure 9-7, there is [alveolar/interstitial] disease. The normalinterstitial markings [are/are not] visible within the consoli-dated areas. This concept is similar to the [silhouette sign/airbronchogram sign] because water density lung is in directcontact with the water density pulmonary vessels (interstitium).

13Alveolar consolidation causes a silhouette sign with thediaphragm, heart, or aorta only if they are _____________. Thesilhouette sign is usually [present/absent] in interstitial diseasebecause _____________ is adjacent to these structures.

14The air bronchogram (remember the air bronchogram?) is usu-ally seen in [alveolar/interstitial] disease because the major air-ways are [open/plugged] but surrounded by consolidated(water density) lung. In interstitial disease, the bronchi are stillsurrounded by _____________.

12alveolarare notsilhouette sign

13

in direct contactabsentaerated lung

14

alveolaropen

aerated lung

We have just learned that most diffuse interstitial lung disease is chronic. Most alveolar disease (airspace consolidation), whether focal, multifocal, ordiffuse, is acute. With alveolar disease, the airspaces are filled with fluid (e.g., edema, blood, mucus, pus, or cells), making the lung appear airless (radiodense, opaque, consolidated). The alveolar pattern may be relativelyhomogeneous (a lobe or segment) or patchy and scattered throughout the lung.

Figure 9-8 shows airspace consolidation of the right upper lobe, an air bron-chogram (arrows), and a silhouette sign of the upper heart and mediastinum—three important signs of alveolar filling disease. There is also focalconsolidation of the right lower lobe without an air bronchogram or silhouettesign.

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FIGURE 9-9

FIGURE 9-10 A

FIGURE 9-10 B

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15To recap:

(a) With alveolar consolidation, the air bronchogram isabsent if _____________.

(b) With alveolar consolidation, the silhouette sign is absentif _____________.

(c) The air bronchogram and silhouette signs are usuallysigns of _____________.

16Figure 9-9 is an example of multifocal alveolar disease. Withinthe areas of consolidation, the interstitial markings are [visible/not visible]. Air bronchograms are more frequently absent in[large/small] areas of alveolar consolidation. The age of thelesion is assessed most accurately with _____________. Historyis helpful but less reliable.

15(a) fluid fills the

bronchi (or centralobstruction)

(b) The consolidation isnot in direct contactwith water densitystructure

(c) alveolar (airspace)consolidation

16

not visible

smallold radiographs

Clinical Pearl: The most frequent causes of acute diffuse alveolar disease(airspace filling disease) are bacterial pneumonia and severe pulmonaryedema. The most frequent cause of acute focal alveolar consolidation is alsoinfection. Subacute alveolar consolidation is often granulomatous infection(tuberculosis, fungal).

To make life difficult, some diseases have alveolar consolidation and interstitialthickening. Figure 9-10A shows focal left upper lobe alveolar consolidation and diffuse interstitial thickening in a patient with silicosis. Figure 9-10B showsthe two patterns nicely. Note the interstitium is sharp and distorted.

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FIGURE 9-12

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17In Figure 9-11A, there are two focal [alveolar/interstitial]opacities on the right. They have [distinct/indistinct] margins.

18(1) In Figure 9-11A, the larger opacity (A) measures greater

than 3 cm. It is termed a _____________.(2) In Figure 9-11A, the smaller opacity (B) measures 1.2 cm

and is termed a _____________.(3) In Figure 9-11B, just above the diaphragm, there is a

_____________.

19When any alveolar lesion (infiltrate, mass, nodule) becomesnecrotic or caseous, the liquefied material is usually expecto-rated and replaced with _____________. The center of the cavitybecomes [radiodense/radiolucent].

17alveolardistinct

18(1) mass

(2) nodule

(3) spot on the lung

19

airradiolucent

An important form of focal alveolar consolidation is the mass or nodule (the famous “spot on the lung”). If a very focal area of consolidation has well-defined borders and measures greater than 3 cm, it is referred to as a“mass.” If it is less than 3 cm, it is called a “nodule.”

Clinical Pearl: In young patients, chronic alveolar consolidation, nodules, andmasses are most often due to indolent infection or inflammatory lung disease. In patients older than age 40, cancer becomes a major concern.

Figure 9-12 shows multiple masses, two of which are cavitary (arrows).

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FIGURE 9-13 A

FIGURE 9-14 FIGURE 9-15 A FIGURE 9-15 B

FIGURE 9-13 B

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20If the necrotic material is only partially expelled, air and fluidremain in the cavity. When the patient is erect, the fluid settlesto the bottom, and the air rises to the top. This air-fluid level is visible only when the x-ray beam is [parallel/perpendicular]to the air-fluid interface. An air-fluid level is not seen in[erect/supine] radiographs, because _____________.

21Figures 9-13A and 9-13B show x-rays of a Styrofoam cup half full of water. Which was taken with a horizontal x-ray beam? _____________. How did you decide? _____________. In Fig. 9-13B, the cup margin (arrow) is very sharp, but thewater margin (arrowhead) is less sharp. The top of the watercolumn is wider than the bottom. One is looking down at twoedges not quite superimposed.

22In granulomatous infections, if caseous material is not expelled,it may heal and organize into a granuloma. Granulomasfrequently calcify. Figure 9-15A shows a nodule in the left mid lung. It is [more dense/less dense] than the rib; therefore it is of _____________ density. This is most likely a [healedscar/cancer/active tuberculosis]. Figure 9-15B shows the samegranuloma on CT.

20

parallel

supine; x-ray beam isperpendicular to air-fluid level

21

Figure 9-13A; parallel tointerface, see air-fluidlevel

22

more densecalcium, metallichealed scar

Question: Is a glass half full or half empty? (1) It depends on who is pouring and who is drinking. (2) It is neither. The glass is just too big. (3) Half full = 1/2 ×1 = 1/2. Half empty = 1/2 × 0 = 0, obviously wrong. (From geekswithblogs.net.)

Figure 9-14 shows an air-fluid level (arrow) in a cavitary right upper lobepneumonia. Compare with Figure 9-12, where there is no fluid in the cavities.

Clinical Pearl: Heavy calcification is an important sign of benign disease in the lung. Healed tuberculosis and histoplasmosis are the most frequent causes of lung granulomas. The adjacent hilar lymph nodes often calcify (Figure 9-15B).

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FIGURE 9-16 C

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23On the frontal view, diaphragmatic changes indicate hyper-inflation. In Figure 9-16A, the diaphragms are flat and[normal/high/low]. They are lower than the _____________posterior rib. The diaphragms are normally at the [7th-8th/9th-10th//11th-12th] posterior rib.

24Hyperinflation also is seen on the lateral. In Figure 9-16B, the sternum is [normal/bowed/sunken]. The “retrosternal clear space” (R), the area between the ascending aorta and the sternum, is [normal/increased/decreased]. The AP diame-ter is increased (i.e., barrel chest). The diaphragms are_____________ and _____________.

25The combination of hyperinflation and _____________ indicatesemphysema.In Figure 9-16C, note the cystic spaces and distortion caused bythe thin walled bulla.

23

low (depressed); 10th;9th-10th (below 10th =hyperinflation)

24

bowed

increased

flat; depressed (low)

25bullae (sparse ordistorted markings orlung destruction)

Few conditions cause the lung to be more radiolucent. If the lung is hyperin-flated, it becomes hyperlucent because a fixed amount of tissue is spread over alarger volume. If the interstitium is destroyed (e.g., bulla formation), the lungbecomes more hyperlucent because there is less tissue to absorb radiation.Bullae or sparse markings replace normal branching vessels (Figure 9-16A).

In real life, these nice neat patterns of lung disease often overlap. However, thisapproach provides a way of organizing your descriptions to form a differentialdiagnosis.

Anagram: Snooze alarms = _____________.

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FIGURE 9-17 A

FIGURE 9-17 B

FIGURE 9-17 C

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REVIEW

IRadiologic signs of diffuse interstitial lung disease:

1. “Pulmonary markings” are [more/less] visible.2. The lung appears [aerated/not aerated].3. An air bronchogram is [often/seldom] visible.4. The silhouette sign [is/is not/may be] visible.5. Two signs of chronic disease include _____________ and

_____________.

IIRadiographic signs of alveolar filling disease or airspace con-solidation:

1. Vessels are [more/less] visible in the area of disease.2. The diseased lung appears [aerated/not aerated].3. An air bronchogram [is/is not/may be] visible.4. A silhouette sign [is/is not/may be] visible.

IIIIn Figures 9-17A and 9-17B, the patient has two diseases.

A. The patient has what generalized lung disease?_____________.

B. There is also a _____________ in the _____________ lobe(arrowheads on Figure 9-17B).

C. He has had one too many [drinks/cigarettes/lovers].D. On Figure 9-17C, how does CT confirm your suspicions

about his x-ray findings and his personal habits? (Use allthe information on the film!) _____________.

E. The mass is almost certainly _____________.

I

1. more2. aerated3. seldom4. is not5. distortion, honey-

combing, sharpmargins, no serialchange

II

1. less2. not aerated3. may be4. may be

III

A. chronic obstructivepulmonary disease(COPD) (emphysema)

B. mass, right upperC. cigarettesD. right upper lobe

mass, bulla, ciga-rettes and lighter inleft breast pocket

E. lung cancer

Anagram: Snooze alarms = Alas, no more Z’s!

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FIGURE 10-1 A

FIGURE 10-1 B

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155

TEN

THE MEDIASTINUM

The mediastinum is the area between the right and left lung, bounded by the medial parietal pleura. Mediastinal diseases can be difficult to detect on chest x-ray because mostdiseases are of soft tissue density and are surrounded by other soft tissue structures.Mediastinal lesions may cause local or diffuse widening; displace, compress, or invadeadjacent structures; or cause a silhouette sign with adjacent structures.

1Let’s review the mediastinal borders. On Figure 10-1A, identifythe following:

A = _____________B = _____________C = _____________D = _____________E = _____________F = _____________G = _____________

(The left and right pulmonary arteries (L and R), which definethe hilum, are outside the mediastinum, in the lung.)

2There is considerable overlap of the mediastinal structures inthe PA view. The lateral view is often helpful for localization. In Figure 10-1B, identify the following:

A = _____________B = _____________C = _____________D = _____________G = _____________L = _____________R = _____________

The lucent area (X) between the sternum and the ascendingaorta is called the _____________.

1

A = ascending aortaB = aortic knob (arch)C = descending aortaD = right heartE = superior vena cavaF = right tracheal wallG = left heart

2

A = ascending aortaB = aortic knobC = descending aortaD = right heartG = left heartL = left pulmonary arteryR = right pulmonary

arteryretrosternal clear space

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FIGURE 10-2 C

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Ten • The Mediastinum 157

3Let us review the CT anatomy of the mediastinum discussed inChapter 4. Figures 10-2A, 10-2B, and 10-2C are three CT scans.They are at [mediastinal/lung/bone] windows. Intravenouscontrast medium [has/has not] been given.

4Figure 10-2A is through the aortic arch. Identify:

A = _____________B = _____________C = _____________D = _____________* = _____________F = _____________

5Figure 10-2B is just below the carina. Identify:

E = _____________F = _____________G = _____________H = _____________J = _____________K = _____________r = _____________

6Figure 10-2C is through the heart. Identify:

L = _____________M = _____________N = _____________O = _____________P = _____________

7The mediastinum completely separates the left and rightpleural spaces in every animal but the _____________. (“Man isthe missing link between animals and human beings.”—KonradLorenz)

3mediastinal; has

4A = ascending aortaB = descending aortaC = superior vena cavaD = trachea* = aortic archF = esophagus

5E = main pulmonary

arteryF = left pulmonary

arteryG = ascending aortaH = descending aortaJ = right main stem

bronchusK = right hilum

(pulmonary vessels)r = normal-sized

lymph nodes

6L = right ventricleM = left ventricleN = descending aortaO = dome of

diaphragm (liver)P = esophagus

7

Lymph nodes of less than 1 cm are frequently seen on CT in normal individuals.

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FIGURE 10-3 A


FIGURE 10-3 B

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8The most frequent sign of mediastinal disease is mediastinalwidening. Most masses cause [focal/generalized] widening.Infiltrating diseases, such as hemorrhage or infection, usuallycause [focal/generalized] widening.

9Figures 10-3A and 10-3B show two cases of mediastinal disease.Which is likely due to tumor? _____________. Why?_____________. Which is likely due to hemorrhage?_____________. Why? _____________.

10A mediastinal mass displaces the medial pleura toward thelung. The interface with the lung is usually [sharp/indistinct]and [concave/convex].

11Masses in an enclosed space such as the mediastinum also may displace, compress, or invade adjacent mediastinal struc-tures. In Figure 10-4A, the trachea is [midline/displaced], and itslumen is [open/narrow]. In Figure 10-4B, the trachea is[midline/displaced], and the lumen is [open/narrow].

8

focal

generalized

9

Figure 10-3Atumor is focalFigure 10-3Bhemorrhage is diffuse

10

sharpconvex (toward thelung)

11

displacednarrowmidline; narrow(compressed)

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FIGURE 10-5

FIGURE 10-6

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12Finally, a mediastinal mass may obscure an adjacent structureof the same density, the _____________ sign. This helps tolocate the mass. Figure 10-5 shows a large mass obliterating the_____________ border. Because the trachea is in the middlemediastinum, this is a _____________ mediastinal mass. Notetracheal displacement and marked narrowing (arrows).

13The radiologist divides the mediastinum into three compart-ments based on the lateral chest x-ray. In Figure 10-6, an imagi-nary line separates the anterior (I) and middle mediastinum (II).The line sits in front of the trachea but behind the_____________. A second line, 1 cm back from the anterior edge of the vertebral bodies, separates the _____________mediastinum from the _____________ mediastinum.

14The anterior mediastinal compartment sits between the sternumand a line drawn anterior to the _____________ and posterior tothe _____________. On the lateral x-ray, the upper portion is thearea of the retrosternal clear space.

12

silhouette

right tracheal (rightmediastinal)middle

13

heartmiddleposterior

14

tracheaheart

For convenience of differential diagnosis, the mediastinum is divided into threecompartments: anterior, middle, and posterior. There are several methods ofdividing the mediastinum. None is perfect because structures and diseases oftencross these artificial divisions. Felson’s is the simplest (and we like simple).(“Get the facts first and then distort them as you please.”—Mark Twain)

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FIGURE 10-7 A

FIGURE 10-7 B

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15The lateral radiograph is often helpful in assigning disease toone of the mediastinal compartments. In Figure 10-7A, the masssits in the _____________ mediastinum. It fills the retrosternalclear space. (Compare with Figure 10-1B.)

16What lesions cause anterior mediastinal masses? “Snow Whiteand the Seven Dwarfs” dwell in the forest. “Big White and theFive T’s” dwell in the anterior mediastinum. Big White is the_____________ and the five T’s are named Thyroid, Thymus,Teratoma, Thoracic aorta (ascending), and Terrible lymphoma.(Big White is discussed in Chapter 12.)

17The anterior edge of the middle mediastinum is a line anteriorto the _____________ in the upper chest and posterior to the_____________ in the lower chest. The posterior margin of themiddle mediastinum is formed by a line drawn _____________.

18A review:

(1) Most mediastinal masses cause a _____________ widen-ing of the mediastinum.

(2) Most mediastinal infiltration (blood, infection) causes a_____________ widening of the mediastinum.

(3) In both cases, the interface with the lung is usually[sharp/indistinct] and [toward/away from] the lung.

(4) Secondary signs of mediastinal disease include invasion,_____________, _____________, and a _____________ sign.

15

anterior

16

heart

17

tracheaheart1 cm behind anterioredge of vertebralbodies

18

(1) focal

(2) diffuse

(3) sharp; toward(convex)

(4) displacement,compression,silhouette

Figures 10-3A and 10-7A show a thymic mass in the same patient. Generally, it isdifficult to differentiate one anterior mediastinal mass from another on thechest x-ray. CT is often helpful in delineating boundaries. In Figure 10-7B, CTshows a homogeneous anterior mediastinal thymic mass with sharp margins,just anterior to the ascending aorta.

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FIGURE 10-8 A

FIGURE 10-8 B

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19Which of the following structures are located in the middlemediastinum?

esophaguslymph nodesspinal nervesheartarch and descending aortatrachea

20In Figure 10-8A, there is a lobulated mass obscuring the righttracheal border. The trachea is located in the _____________mediastinum. This is a _____________ mediastinal mass. Themass is _____________ toward the lung and is lobulated, but hassharp borders.

21The three major middle mediastinal organs are esophagus, tra-chea, and aorta (arch and descending). Most middle mediastinalmasses arise, however, from the _____________.

19

esophaguslymph nodes (in allthree compartments)arch and descendingaortatrachea

20

middlemiddleconvex

21

lymph nodes

Figure 10-8B is a CT scan showing the enlarged lymph nodes to the right of and anterior to the trachea (T), in the middle mediastinum. The trachea is notcompressed.

Clinical Pearl: Enlarged lymph nodes are the most frequent cause of a middlemediastinal mass. Middle mediastinal adenopathy is most often due to sarcoido-sis in young patients and lung cancer in older patients.

To discourage thieves, the farmer posted a sign: “Caution, one of these cabbageshas been poisoned.” The next morning, he found the sign read: “Caution, two ofthese cabbages have been poisoned.”

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FIGURE 10-9 A

FIGURE 10-10 A

FIGURE 10-9 C

FIGURE 10-9 B

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22In the middle mediastinum, if one suspects an esophageallesion, the appropriate examination would be [CT/barium swal-low/MRI]. If one suspects a solid tumor, adenopathy, or a tra-cheal lesion, the appropriate examination would be [CT/bariumswallow/MRI]. Figures 10-9A and 10-9B show an air-containingmass behind the heart. Figure 10-9C is a lateral view of a bariumswallow (esophagram) showing the large hiatal hernia (stom-ach above diaphragm). (E = esophagus; S = stomach.)

23Don’t forget that vascular structures also traverse the medi-astinum. The ascending aorta is in the [anterior/middle/poste-rior] mediastinum on the right, and the aortic arch is in the[anterior/middle/posterior] mediastinum as it crosses from rightto left. The descending aorta usually sits anterolateral to theanterior margin of the vertebral bodies. In Felson’s classification,the descending aorta is a _____________ mediastinal structure.As it elongates with age, it usually overlaps the spine on the lateral.

22

barium swallow

CT (or MRI)

23

anterior

middle

middle

FIGURE 10-10 B

Primary tracheal lesions are rare, but keep your eye on the trachea because it is often deviated or narrowed by adjacent lesions.

In Figure 10-10A, an aneurysmal aortic arch projects as a mass. Note the calci-fied (atherosclerotic) intima of the aortic arch (upper arrow). The tortuousdescending aorta is lateral to the heart (lower arrow). Figure 10-10B shows thetortuous descending aorta (arrow) overlapping the spine. A feeding tube showsthe normal course of the esophagus—a middle mediastinal structure.

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FIGURE 10-11 A

FIGURE 10-11 B

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24The posterior mediastinum sits between a line _____________and the posterior ribs. More simply, the posterior mediastinumis the paravertebral area.

25In Figure 10-11A, a large mass overlies the spine. It may be in thelung or in the _____________. The arrows point to a destroyedand collapsed vertebral body, suggesting that this mass is inthe _____________. Figure 10-11B shows multiple myeloma of thevertebral body producing the paraspinous mass and expandingthe vertebral body and adjacent rib (arrow = normal rib).

241 cm behind anterioredge of the vertebralbodies

25

posterior mediastinum

posterior mediastinum

Figure 10-12, an MRI image, shows a neural tumor. The vertebral body (V) isintact, but a soft tissue mass (M) protrudes through the neural foramen into theposterior mediastinum. The descending aorta (x) is normal.

Clinical Pearl: Most posterior mediastinal masses are from the nerves or theircoverings (e.g., neurofibroma, meningocele) in younger patients. Multiplemyeloma and metastatic spine diseases are more common in older patients.

Name the three birds of the mediastinum:(1) esopho-goose; (2) azi-goose; (3) thoracic-duck

FIGURE 10-12

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FIGURE 10-13 A

FIGURE 10-13 B

FIGURE 10-13 C

FIGURE 10-14

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26Infection, hemorrhage, adenopathy, and infiltrating tumor mayinvolve several mediastinal compartments. This usually causesa [focal/generalized] mediastinal widening.

27The mediastinum sits [central/lateral] to the medial parietalpleura. The hilum sits [inside/outside] the mediastinal pleura.On the normal chest x-ray, the visible structures we call thehilum are really the _____________. They taper as they courseperipherally. Normal hilar nodes are not visible on the chest x-ray. In Figure 10-14, there is bilateral hilar adenopathy. The hila are lumpy because of the enlarged nodes.

26

generalized

27centraloutside

pulmonary vessels(arteries, veins)

In Figure 10-13A, there is diffuse widening of the mediastinum after trauma. In Figure 10-13B, the CT scan shows fluid (blood) surrounding the aortic arch. Figure 10-13C is a multiplanar reconstruction of the aorta, showing a post-traumatic pseudoaneurysm (arrow).

Clinical Pearl: The most common cause of a hilar mass is adenopathy or anadjacent tumor.

The chest x-ray is reasonably sensitive in detecting mediastinal lesions.Additional imaging usually is required to characterize the abnormality. This iswhere your clinical understanding of the patient ’s history and physical findingsdefines the next appropriate imaging test. There are many different examinationsto choose from. It is often helpful to check with the radiologist. You may even getdifferent answers from different radiologists.

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FIGURE 10-15 A

FIGURE 10-15 C

FIGURE 10-15 B

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REVIEW

IA. There are _____________ jokers in a deck.B. There are _____________ stooges.C. There are _____________ horsemen.D. There are _____________ T’s in the anterior medi-

astinum.The T’s are _____________, _____________, _____________,_____________, and _____________.

IIFor each named structure, give the mediastinal compartment:

1. esophagus: ____________________2. heart: _________________________3. thymus: _______________________4. trachea: _______________________5. thyroid: _______________________6. spinal nerves: __________________7. lymph nodes: __________________8. aorta, ascending: _______________9. aorta, descending: ______________

10. aortic arch: ____________________

IIIFigure 10-15A is a PA radiograph of a middle-aged man.

1. The mediastinum is [normal/diffusely widened/focallywidened].

2. The trachea is _____________ and [narrowed/notnarrowed].

3. These findings suggest [tumor/infection] of the [anterior/middle/posterior] mediastinum.

4. [The right hilum/The left hilum/Both hila] is/are big.

IA. 2B. 3C. 4D. 5

thyroid; thymus;teratoma; thoracicaorta; terriblelymphoma

II

1. middle2. anterior3. anterior4. middle5. anterior6. posterior7. all three8. anterior9. middle

10. middle

III

1. focally widened(right and left)

2. displaced; notnarrowed

3. tumor; middle

4. The right hilum

Figures 10-15B and 10-15C are axial and coronal images through the medi-astinum and hilum. Note large nodes (N). This patient has lymphoma.

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FIGURE 11-1 A

FIGURE 11-1 C

FIGURE 11-1 B

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175

ELEVEN

THE PLEURAL ANDEXTRAPLEURAL SPACES

The pleural cavity is a true space between the visceral and parietal pleura. The extrapleuralspace, a potential space, lies between the rib cage and the adherent parietal pleura. Eachproduces characteristic radiographic signs of disease, with the usual overlapping of signs.

1The periphery of the base of each pleural cavity forms a deepgutter around the dome of the corresponding hemidiaphragm.This is called the costophrenic sulcus or angle. The deepestand most caudal portion of the _____________ angle (sulcus) isposterior. The lateral costophrenic sulcus is also fairly deep.

2The [anterior/posterior/lateral] costophrenic angle is deepestand seen only on the _____________ radiograph. It is not visibleon the PA radiograph because the dome of the diaphragm is[above/below] it. On the PA view, fluid is best detected in the_____________ costophrenic angles.

3Romeo, shown in Figures 11-1A and 11-1B, slammed the backdoor just as the husband fired. The bullet, almost spent, justpenetrated his chest wall and dropped harmlessly into thepleural space. Figures 11-1A and 11-1B illustrate the depth ofthe _____________ costophrenic angles and the hazards of sex.(Editor’s note: Things were simpler in Dr. Felson’s time.)

1

costophrenic

2posteriorlateral

abovelateral

3

posterior

In Figure 11-1A (upright film), the bullet in the posterior costophrenic angleappears to lie in the abdomen. In Figure 11-1B (lateral film), the bullet is clearlyin the costophrenic angle. In Figure 11-1C (supine film), several days later, thebullet has shifted in the pleural space.

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FIGURE 11-2 A FIGURE 11-2 B FIGURE 11-2 C

FIGURE 11-3 A FIGURE 11-3 B FIGURE 11-3 C

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Eleven • The Pleural and Extrapleural Spaces 177

4Free pleural fluid (e.g., blood, exudate, transudate) is heavierthan the air-filled lung and sinks to the base of the pleural cavity in the [upright/supine] position. It causes the normallydeep _____________ and _____________ costophrenic angles toappear shallow or blunted. In Figure 11-2A, the lateralcostophrenic sulcus is normal. In Figure 11-2B, the lateralcostophrenic angle is _____________ because of a small effu-sion. Additional fluid tracks up the pleural space, forming ameniscus, as shown in Figure 11-2C. Figures 11-2A, 11-2B, and11-2C are all the same patient.

5On the lateral x-ray, the signs are exactly the same. In Figure 11-3A, both costophrenic angles are _____________. In Figure 11-3B, the left costophrenic sulcus is _____________. In Figure 11-3C, fluid forms a _____________, posteriorly.

6In Figure 11-3C, only the [left/right] diaphragm is visible. Why? _____________.

4

upright;posterior; lateral

shallow (blunt)

5

sharp (normal)shallow (blunt)meniscus

6rightright contacts air in lung,and left contacts pleuralfluid

Pleural fluid is often seen tracking up the major fissure on the lateral examina-tion, a helpful secondary sign of pleural effusion (arrows on Figures 11-3B and 11-3C).

Clinical Pearl: The lateral film is more sensitive than the PA film for thedetection of small effusions. If there is a discrepancy between them, believe thelateral. Figure 11-2 and Figure 11-3 are of the same patient. Compare each set of PA and lateral examinations.

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FIGURE 11-4 A

FIGURE 11-4 B

FIGURE 11-4 CFIGURE 11-4 D

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7As you get older, gravity is less and less a friend. In radiology,however, gravity can be a friend. What view would be mosthelpful in proving that Figure 11-4A has a subpulmonic effusion?_____________. The affected side should be [up/down] to displaythe layered fluid.

8Let’s review the signs of pleural effusion on the PA radiograph.A small effusion _____________ the costophrenic angle. A largereffusion forms a _____________ laterally, or hides in a_____________ location. Remember, these are seen only in the[upright/supine] position.

7

left lateral decubitus;down

8

blunts (fills)meniscussubpulmonicupright

In Figure 11-4A, the apparent elevation of the left hemidiaphragm is actuallysubpulmonic fluid. The true diaphragm lies in normal position, but is obscuredby a parallel layer of free fluid. In the upright position, free fluid often collectsbetween the lung base and the top of the diaphragm. This “subpulmonic effusion”makes the “diaphragm” appear elevated.

Figure 11-4B is a left lateral decubitus view of the patient shown in Figure 11-4A.The free fluid has redistributed to the dependent side of the left pleural cavity,between the lung and chest wall. Figure 11-4C, a CT scan, shows a gravity-dependent pleural effusion layered posteriorly (E). In Figure 11-4D, ultrasoundshows a free subpulmonic effusion (E) (arrow = diaphragm.)

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FIGURE 11-5

FIGURE 11-6 A

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9We are now faced with the practical problem of recognizingsubpulmonic fluid because it so closely simulates an_____________. On the left, the stomach bubble is normallyseparated from the lung base by only the thin diaphragm.Figure 11-5 shows the normal distance between the stomachand the lung (arrow). In Figure 11-6A, with left subpulmonicfluid, the gas bubble lies [farther from/closer to] the lung base.This is known as the “stomach bubble sign.”

10Compare Figures 11-5 and 11-6A.

A. In Figure 11-6A, the left costophrenic angle is_____________, but a _____________ sign tells us there isa left effusion.

B. What are the signs of pleural effusion on the right?_____________.

9

elevatedhemidiaphragm

farther from

10

A. sharp; stomachbubble

B. right costophrenicangle blunt,diaphragm changesshape

FIGURE 11-6 B

There is no stomach bubble on the right. We often have to rely on the change ofshape of the right “diaphragm” to diagnose subpulmonic effusion. In Figure 11-5,the apex of each diaphragm is in the mid clavicular line. With subpulmoniceffusion, often the apex of the “diaphragm” moves to a more lateral position orchanges shape, a helpful sign on either side.

In Figure 11-6B, the lateral x-ray shows blunting of both costophrenic angles posteriorly and a stomach bubble sign. There is also fluid in a major fissure(arrow).

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FIGURE 11-7


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11With a subpulmonic effusion:

1. The “diaphragm” appears _____________.2. The apex of the “diaphragm” may shift [laterally/

medially].3. The costophrenic angle may be shallow or show a

_____________.4. The stomach may be _____________.5. How would you confirm suspicions on the PA image?

_____________.

12In the AP supine position, the fluid gravitates [anteriorly/posteriorly] and causes the affected hemithorax to appear[more/less] radiodense. The supine patient in Figure 11-7 has a[left/right] pleural effusion. The supine view is [more/less]sensitive than the erect view in detecting effusion.

13When one hemithorax is totally opaque, is it usually due to con-solidation and atelectasis, or is it due to a large _____________?If the “white lung” is due to atelectasis, the mediastinum shifts[toward/away from] the lesion. If the “white lung” is due to pleu-ral fluid, it shifts [toward/away from] the lesion.

14Compare the “white lungs” of Figures 11-8A and 11-8B.

A. Figure 11-8A is due to _____________. Why?_____________.

B. Figure 11-8B is due to _____________. Why?_____________.

15Encapsulated (loculated) pleural effusion is attributable topleural adhesions, preexisting or developing after the appear-ance of the fluid. It [does/does not] shift with changingpositions.

11

1. high, changes shape2. laterally

3. meniscus

4. distant from lung5. lateral or lateral

decubitus film

12

posteriorlymoreleft; less (considerably)

13

pleural effusion

towardaway from

14

A. pleural effusion;contralateral shift

B. atelectasis; ipsilat-eral shift

15

does not

Clinical Pearl: Every student wants to know how much fluid one can see on aradiograph. The erect PA requires greater than 175 mL; the erect lateral, 75 mL;the decubitus, greater than 5 mL; the supine, more than several hundredmilliliters. Now you know. (Does the name Pavlov ring a bell?)

Clinical Pearl: If there is a “white hemithorax” but no shift, both atelectasis andeffusion may be present. There is a balance between collapse and pleural fluid,or a tumor “anchors” the mediastinum, preventing a shift.

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FIGURE 11-9 A

FIGURE 11-10 A

FIGURE 11-9 B

FIGURE 11-10 B

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16Loculated fluid may simulate lung disease. See Figure 11-9A, an example of loculated pleural fluid. The borders of an encap-sulation are generally [concave/convex] toward the lung. The margin forms an [obtuse/acute] angle with the chest wall when seen in profile (arrows). An air bronchogram is[present/absent].

17Occasionally, fluid accumulates in a fissure. It may look like a lung mass. Because it splits the fissure, this “pseudotumor” is often [lenticular/spherical] in shape.

18Intrafissural effusion (“pseudotumor”) is bounded by visceralpleura, and its margins appear [sharp/hazy] when seen in pro-file (on edge). The encapsulated effusion in the minor fissureshould have sharp margins in [the PA/the lateral/both] view(s).The margins of the “mass” in the major fissure should be sharpin [the PA/the lateral/both] views(s). (Remember, the beammust be parallel to the fissure to see it.)

16

convexobtuse

absent

17

lenticular

18

sharp

both

lateral

Figure 11-9B, a CT scan of the loculated fluid, shows a similar appearance(arrows). There is a second smaller loculation as well. Compare this with thefree effusion of Figure 11-4C.

Figures 11-10A and 11-10B show the minor fissure “pseudotumor” (A) has sharpmargins in the PA and lateral. The two loculated collections in the major fissure(B and C) are completely sharp only in the lateral projection. On the frontalimage, portions of the major fissure pseudotumors are indistinct.

Clinical Pearl: “Pseudotumors” are most commonly encountered in congestiveheart failure. As the congestive heart failure resolves, the loculated fluiddisappears (“vanishing tumor”).

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FIGURE 11-11 A

FIGURE 11-12 A

FIGURE 11-12 B

FIGURE 11-11 B

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19Air in the pleural space is [more/less] radiolucent than the lung.With a pneumothorax, the visceral pleura is seen as a thin whiteline between air in the lung and air in the _____________. Whenthe lung is consolidated, the pneumothorax appears as a(n)[line/edge] adjacent to the air in the pleural space.

20In a supine patient, air collects [anteriorly/posteriorly] and[inferiorly/superiorly]. In Figure 11-12A, we see what two signsof pneumothorax? _____________ and _____________. Note thesubpulmonic air. Figure 11-12B shows air anterior to the lungon a CT scan of a supine patient.

21The supine film is [more/less] sensitive than the erect film fordetecting pneumothorax. If the patient cannot sit or stand, the _____________ position may be substituted. The side inquestion should be [up/down].

19more

pleural space

edge

20anteriorlyinferiorlyhyperlucent pleural space(no lung markings); vis-ceral pleural line (arrows)

21less

decubitusup

Figure 11-11A shows the pleura on end between the pleural air and the aeratedlung (arrows). Figure 11-11B shows the pleural air against the edge of theconsolidated upper lobe (arrow). There are no lung markings in the air-filledpleural space. There is also air in the subcutaneous tissues (arrowhead).

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FIGURE 11-13

FIGURE 11-14 A

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22Occasionally, air enters the pleural space with each breath butcannot escape, increasing the intrapleural pressure. The increasedpressure [elevates/depresses] the diaphragm, collapses thelung, and shifts the mediastinum [toward/away from] thepneumothorax. This is known as a “tension pneumothorax.”

23Tension pneumothorax compromises pulmonary venous returnand is a medical emergency. In Figure 11-13, we see the pleuralline and air in the pleural space, signs of pneumothorax. Thethree radiographic signs that indicate a tension pneumothoraxare _____________, _____________, and _____________. The ribson that side may be further apart.

24A hydropneumothorax is air and fluid in the pleural space. Onthe erect film, the lower pleural space fills with _____________,the upper pleural space fills with _____________, and an_____________ is visible at their interface.

22

depresses (flattens)away from

23

collapsed lung; depresseddiaphragm; shifted medi-astinum

24

fluidairair-fluid level

FIGURE 11-14 B

Clinical Pearl: Rapid decompression of a tension pneumothorax can belifesaving. Learn the clinical signs so that you can diagnose and treat it without an x-ray. Signs include rapid onset of respiratory failure, decreased breathsounds, deviated trachea, and jugular venous distention.

In Figures 11-14A and 11-14B, the left lung was removed for cancer. There is fluidin the lower pleural space, air in the upper pleural space, and an air-fluid level.The air bubble in the stomach is elevated, indicating diaphragmatic elevationbecause the lung has been removed.

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FIGURE 11-15


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25The extrapleural space is a potential space that lies betweenthe rib cage and the pleural space. Lesions that arise instructures within or bordering the extrapleural space (e.g., ribs,muscle, connective tissue) may lift the adjacent [parietal/visceral] pleura and push it toward the lung. A typicalextrapleural lesion is convex with a [sharp/hazy] interface withthe lung. It forms an [acute/obtuse] angle with the chest wallwhen viewed in tangent.

26A focal intrapleural lesion (encapsulated fluid) and anextrapleural lesion can form [acute/obtuse] angles with thechest wall and a [sharp/hazy] lung interface. The presence of arib lesion indicates a(n) [pleural/extrapleural] origin. If none isvisible, it may be difficult to separate the two.

27Cross-sectional imaging helps separate extrapleural fromintrapleural lesions by eliminating overlap of structures. Figure11-16A, a computed radiograph, shows a mass that forms an[acute/obtuse] angle with the chest wall. The CT scan in Figure11-16B shows that this mass is [intrapleural/extrapleural]. Howdid you decide? _____________.

25

parietal

sharpobtuse

26

obtusesharpextrapleural

27

obtuseextrapleural; expansileirregular rib lesion, softtissue mass

Figure 11-15 illustrates an extrapleural lesion. The convex margin facing thelung is sharp, and the borders are tapered (obtuse angle with chest wall). Thelesion looks similar to encapsulated fluid (see Figure 11-9A). The rib fractures(arrowheads in Figure 11-15) indicate the extrapleural origin.

Clinical Pearl: Most extrapleural lesions are due to rib fractures (see Figure 11-15)and rib metastasis (see Figure 11-16B).

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FIGURE 11-17 A

FIGURE 11-17 B

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REVIEW

IA. What are the three patterns seen with free pleural effusionsseen on an erect film?

(1) _____________.(2) _____________.(3) _____________.

B. List four clues to a subpulmonic effusion:(1) _____________.(2) _____________.(3) _____________.(4) _____________.

IITo diagnose a pneumothorax, one must see:

(1) _____________.(2) _____________.

IIIFigures 11-17A and 11-17B are supine x-rays of a young womanwho was in an auto accident.

A. On the left, there is [increased/decreased] radiodensity,which is most likely due to _____________.

B. On the right, there is [increased/decreased] radiolu-cency, which is due to _____________.

C. The mediastinum is [normal/focally widened/generallywidened], which is most likely due to _____________.

D. Her choice of jewelry indicates _____________.

IA.(1) blunt costophrenic

angle(2) meniscus(3) subpulmonic

effusionB.(1) high “diaphragm”(2) stomach bubble

sign(3) “diaphragm” apex

shifts, changesshape

(4) shallowcostophrenic angleor thickened fissure

II(1) peripheral

hyperlucency(intrapleural air)

(2) visceral pleural lineor edge

IIIA. increased; layered

pleural fluid (blood)B. increased;

pneumothorax(see visceral pleuralline)

C. generally widened;hemorrhage

D. . . . . . .

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FIGURE 12-1 A

FIGURE 12-1 B

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195

TWELVE

CARDIOVASCULARDISEASE

To analyze cardiovascular disease fully, the heart, pulmonary vessels, lungs, and pleuralspace all must be studied. Every beginner should be able to recognize the cardiovascularstructures, cardiomegaly, and left heart failure. If you can, you will be ahead of most of your peers.

1Figure 12-1A is an x-ray of the heart and great vessels. On theleft side, there are four bulges (moguls to you skiers). They are:

1. _____________.2. _____________.3. left atrial appendage.4. _____________.

2The right heart border is formed by the right atrium (5).The right ventricle does not form a lateral border on the frontalview. Above the right heart border is the _____________ (6).Above the ascending aorta, the _____________ (7) is parallel tothe upper mediastinum.

3On the lateral film, the right heart is anterior, and the left heartis posterior. Label the cardiovascular structures on the lateral(Figure 12-1B).

1. _____________.3. _____________.4. _____________.6. _____________.8. _____________.9. _____________.

1

1. aortic arch2. main pulmonary

artery4. left ventricle

2

ascending aortasuperior vena cava

3

1. aortic arch3. left atrium4. left ventricle6. ascending aorta8. right ventricle9. descending aorta

(proximal)

Two medical students spotted a bear while walking in the woods. Student #1took out sneakers from his backpack and put them on. “You can’t outrun a bear,” said Student #2. Said Student #1, “I don’t have to, I just have to outrun you.”

Note: The normal left atrial appendage is concave, not convex.

Note: In reality, the right heart is anterior and the left heart is posterior—not leftand right.

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FIGURE 12-2

FIGURE 12-3 A

FIGURE 12-3 B

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Twelve • Cardiovascular Disease 197

4Sometimes the terminology is confusing. Review the following:

A. The left heart sits [anterior/posterior] to the right heart.B. On the frontal view, the normal right heart border is

formed by the _____________ only.C. On the frontal view, the left atrial appendage is normally

[concave/convex].

5In Figure 12-2, the cardiothoracic ratio is _____________. Theupper limit of normal is _____________. These measurementsare unreliable on an AP image because of _____________.

6The “heart” may be enlarged because of intrinsic cardiac diseaseor appear enlarged by surrounding pericardial fluid. The x-raydoes not distinguish between cardiac _____________ and pericar-dial _____________. For this reason, many prefer the term“cardiac silhouette” to “heart size.”

7If the left atrium enlarges, it protrudes [laterally/medially] and [anteriorly/posteriorly]. On the frontal view, its marginbecomes [concave/convex].

4

A. posterior

B. right atriumC. concave

50.43 (12/28)0.50cardiac magnification

6

enlargementfluid

7laterallyposteriorlyconvex (mogul 3)

Determining cardiac enlargement is easy. Measure the horizontal width of theheart and divide it by the widest internal diameter of the thorax. The normalcardiothoracic ratio is less than 0.5. (Oversimplified, but useful.)

Clinical Pearl: The cardiothoracic ratio is based on population standards. For a given patient, an increase of greater than 1 cm in cardiac diameter from a prior film is a more reliable index of cardiac enlargement than the cardiotho-racic ratio. In general, a radiologist with a ruler is a radiologist in trouble,but these measurements work fairly well on erect, inspiratory PA radiographs.

Figures 12-3A and 12-3B show an enlarged left atrium. The upper left heartborder bulges laterally (arrow on Figure 12-3A) and posteriorly (arrow on Figure 12-3B). Compare with Figures 12-1A and 12-1B.

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FIGURE 12-4 A

FIGURE 12-5 A

FIGURE 12-4 B

FIGURE 12-5 B

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8In Figures 12-4A and 12-4B, the white arrow points to the _____________. The black arrowhead points to the_____________, and the white arrowhead points to the_____________. The aorta is so tortuous that even the aorticarch is visible.

9To review: A large left atrium bulges _____________ on the PAfilm and _____________ on the lateral film. A large left ventriclebulges _____________ on the PA and _____________ on the lat-eral x-rays.

8

left ventricledescending aortaascending aorta

9laterallyposteriorlylaterally and inferiorlyposteriorly and inferiorly

With left ventricular enlargement on the frontal view, the left heart bordermoves laterally, and the cardiac apex moves inferolaterally. On the lateral view,the left heart border moves inferoposteriorly.

Detecting right heart enlargement is more difficult. In the frontal projection, thenormal right heart protrudes slightly to the right of the spine, and an enlargedheart protrudes further to the right (soft science, at best). In the lateral projec-tion, the right heart enlarges anteriorly and superiorly. The normal right heartcontacts the lower one third of the sternum, whereas the enlarged right heartcontacts the lower one half. Compare the enlarged right heart (Figures12-5A and12-5B) with the enlarged left heart in Figures12-4A and 12-4B.

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FIGURE 12-6 A


FIGURE 12-6 B

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10Many heart diseases also alter the pulmonary vessels. In anormal erect patient, gravity causes most blood to flow to the[apex/base]. In Figure 12-6A, the upper lobe vessels are[larger/smaller] than the lower lobe vessels at approximatelythe same distance from the hilum. In a supine patient, whathappens to blood flow? _____________.

11In Figure 12-6B, the upper lobe vessels are [larger/smaller] thanthe lower lobe vessels. This is called cephalization or vascularredistribution. Cephalization, not heart size, is the key todiagnosing elevated left heart pressure. Compare Figure 12-6Aand Figure 12-6B until cephalization is absolutely clear.

12Look at Figures 12-7A and 12-7B. Which patient has prominentupper lobe vessels as a result of an atrial septal defect?_____________.

10

basesmaller

apex = base, evens out

11larger

12

Figure 12-7A

Clinical Pearl: Left heart failure and mitral valve stenosis are the most frequentcauses of redistribution or cephalization. A shunt (e.g., atrial or ventricularseptal defect) causes all vessels to enlarge.

The patient in Figure 12-6B is in left heart failure. There is enlargement of theupper lobe vessels (cephalization). This is mild left heart failure because thevessel margins remain distinct (i.e., no edema).

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FIGURE 12-8 A

FIGURE 12-8 B

FIGURE 12-8 C FIGURE 12-9

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13As the left atrial pressure increases, interstitial edema develops.The edema causes the vessel margins to become [sharper/lesssharp] and the peripheral interstitial markings to become[more/less] prominent. Figure 12-8A shows mild left heart failure.The upper and lower lobe vessels are equal, and there is noedema.

14In Figure 12-9, there is evidence of severe edema. The edematends to be more severe in the gravity-dependent [upper/lower] lungs. With alveolar edema, the pulmonary vessels maynot be visible. Why? _____________.

15In left heart failure, the cardiac silhouette often enlarges. Inaddition:

A. In mild failure, there is _____________ of the vessels butno edema.

B. Moderate failure causes indistinct vessel margins as aresult of [alveolar/interstitial] edema. _____________lines and pleural effusions may be present.

C. Severe failure causes [alveolar/interstitial] edema andpleural effusions.

13

less sharp

more

14

lowerwater density lungaround water densityvessels

15

A. cephalization

B. interstitial; Kerley B

C. alveolar

Figure 12-8B shows moderate heart failure in the same patient as in Figure 12-8Awith large but hazy upper lobe vessels and prominent interstitium. Fluid thick-ens the interlobular septa, causing short lines perpendicular to the pleuralsurface. These are “Kerley B” lines indicating interstitial edema (arrows). Figure 12-8C is a close-up of Kerley B lines (arrows) in a different patient.

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FIGURE 12-10

FIGURE 12-11

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16Let us go back to Kerley lines. Kerley B lines indicate fluid in the _____________. Kerley also described A and C lines. He wasobviously a splitter, rather than a lumper. We will not worryabout A and C lines. Figure 12-10 is a CT scan of Kerley B lines(arrows).

17Figure 12-11 is a portable radiograph.

1. It is taken [supine/erect].2. The cardiothoracic ratio is _____________.3. The upper lobe pulmonary vessels are _____________.4. Patient [is/is not/can’t tell] in heart failure.

18Name the physiologist whose law described the relationshipbetween edema, hydrostatic pressure, and oncotic pressure:_____________. Figure 12-12 is a _____________.

16

interlobular septa

171. supine (arrow

points down)2. not valid

(magnification)3. prominent, but this

is normal in asupine patient

4. can’t tell

18

Starling; Starling resistor

FIGURE 12-12

Clinical Pearl: With cephalization alone, lung auscultation is usually normal.With interstitial edema, crackling rales are audible. With alveolar edema, ralesare audible.

Determining cardiomegaly and cephalization is unreliable on supine films.

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FIGURE 12-13

FIGURE 12-14

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19Figure 12-13 is a PA radiograph:

A. Cardiothoracic ratio is _____________.B. Is there cephalization? _____________.C. Is there edema? _____________.D. Is there a pleural effusion? _____________.E. There are no significant signs of left heart failure.

Perhaps the large cardiac silhouette is due to a_____________.

19A. greater than 50%,

highB. noC. noD. noE. pericardial effusion

FIGURE 12-15

Figure 12-14, an echocardiogram, shows a large pericardial effusion (P). Figure 12-15,a CT scan of a different patient, shows a pericardial effusion (P), bilateral pleu-ral effusions, and left lower lobe consolidation (atelectasis). Echocardiography,CT, and MRI accurately depict pericardial effusions, but echocardiology is mostcost-effective.

Clinical Pearl: Marked generalized enlargement of the cardiac silhouette, with no or mild signs of left heart failure, is most likely due to pericardialeffusion. Cardiomyopathy and multivalvular heart disease may have a similarradiographic presentation.

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FIGURE 12-18

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BONUS SECTION

Patients with heart or lung disease often wind up in the ICU with many support tubes and catheters. These should beevaluated on every x-ray before your standard search.

20In Figure 12-16, the apparatus is correctly positioned. (L =electrocardiogram lead on skin.)

A. Endotracheal tube (E) with its tip [at the carina/in themid trachea/in the cervical trachea].

B. Central venous catheter (C) is in the _____________.C. Nasogastric tube tip (N) is in the _____________.

21In Figure 12-17 (arrowheads):

A. The endotracheal tube is in the _____________.B. The central venous pressure catheter is in the

_____________.

22Figure 12-18 (L = electrocardiogram lead): X-ray request: “Checknasogastric tube position.” The tube is _____________.

20

A. in the mid trachea

B. superior vena cavaC. stomach

21

A. right main bronchusB. superior vena cava

22

coiled in a hiatal hernia

Congratulations!You are done. (“He who laughs, lasts!”—Leo Rosten). There is no review quiz.Take a break! When you come back, challenge yourself to the dozen great quizcases in the last section. Also, be sure to read Felson’s “Ten Axioms for aLifetime of Learning in Medicine” (next page). The CD on the back cover is wortha look.

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Felson’s 10 Axioms for a Lifetime of Learning in Medicine

1. If you like it, you’ll learn it; so learn to like it.

2. Principles are as important as facts. If you master the principles, you can makeup the facts.

3. You learn better when you know your goals. If you don’t now where you’regoing, says the Talmud, all roads will take you there. But if you do know, you’llget there much quicker.

4. Follow your cases. I’ve learned and remembered more by follow-up than anyother way. It’s hard work, but as Confucius say, “He learneth most who workethmost.” Or was it Knute Rockne?

5. Like sex, learning is better if you are actively involved. When you read, talk backto the author. Be skeptical. Don’t follow the authorities too closely or you maybecome a Brown Nose Duck; he can fly as fast as the leader, but can’t stop asquick.

6. Reinforcement is essential for acquiring knowledge. But don’t reinforce bysimple repetition; use some other method than the original way you learned it.See a case, look it up; read an article, find a case or ask a question.

7. Reward is important for learning. Show off what you know. Brag a little. Speakup in class. Tell your spouse or sweetheart; tell your colleagues; don’t bother totell your friends—you won’t have any.

8. Different people learn best by different methods. Figure out your own best methodand cater to it, whether it be reading, listening, observing, or doing, or a combina-tion of these. Don’t depend on great teachers. They are as rare as great students.

9. Quick retrieval of once-acquired information is crucial. The home computer isideal but other good retrieval methods are available. Create your own personalmodification and keep improving it. Without a recall system you’re a “loser,” anold man with a stuck zipper.

10. Divide your study time into prime time, work time, and sleepy time. Biorhythmsvary widely among students, so develop your own study schedule. Don’t watchtelevision during prime time and don’t read medicine during sleepy time.

Felson, B. Humor in Medicine, 1989; RHA Inc., Cincinnati, Ohio.

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211

QUIZ

A DOZEN GREATCASES

CHALLENGE Each case tests your ability to apply the fundamental principleswe have just gone over and over.

SUGGESTIONS 1. Read the history.2. Evaluate the x-ray with your routine scanning pattern

(ATMLL), making all the pertinent observations.3. Then, and only then, answer all questions before you turn to

the answers on the next page.

Beware of “satisfaction of search.” There is a tendency when reading x-rays to be so thrilled that you have actually found an abnormality that you thenrelax your search. Don’t! Many patients have several abnormalities that you cancombine to arrive at a diagnosis.

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Quiz • A Dozen Great Cases 213

Case 1History: This is a young man with cancer (Figure Q-1).Metal nipple markers have been placed to distinguish nipples, which sometimes show on x-rays, from real pulmonary nodules.

1. Is the lung abnormal? _____________ If so, where? _____________ What? ____________2. Are there any changes to suggest pleural effusion? [yes/no]3. What type of surgery did the patient have? ____________ (Hint: Is anything missing?)4. Diagnosis: Can you combine the history and x-ray findings to suggest a diagnosis?

_____________

FIGURE Q-1

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Case 11. Yes, below the right nipple marker, where the ribs cross, there is a pulmonary

nodule.2. No. The costophrenic angles are sharp. The stomach bubble sign is absent.

Diaphragms are normally shaped.3. The right shoulder has been amputated. A systematic approach helps avoid

embarrassing misses.4. Diagnosis: Patient had a shoulder amputation, most likely for cancer. The nodule is

most likely a pulmonary metastasis. The amputation was for osteosarcoma.

“Intuition is the source of scientific knowledge.”—Aristotle“Aristotle could have avoided the mistake of thinking that women have fewerteeth than men by the simple device of asking Mrs. Aristotle to open hermouth.”—Bertrand Russell

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Case 2History: This is a 30-year-old epileptic with high fever and chills for 5 days (Figures Q-2Aand Q-2B).

1. There is an abnormality in the _____________ lobe.2. Describe the lesion in detail. _____________3. The arrow points to a(n) _____________.4. Diagnosis: Put the x-ray findings and history together for a logical diagnosis.

_____________

FIGURE Q-2 A FIGURE Q-2 B


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Case 21. right upper lobe (it sits on the major fissure and above the minor fissure)2. There is a mass or focal alveolar consolidation with a central cavity, air-fluid level.3. air-fluid level4. Diagnosis: This is a lung abscess in an epileptic who probably aspirated during

a seizure. Tuberculosis, another reasonable possibility, is usually more indolent.Aspiration most often involves the gravity-dependent portions of the lung in a supinepatient (posterior segments of the upper lobes and the superior and posterior basalsegments of the lower lobes).

“It’s what you learn after you know it all that counts.”—Earl Weaver

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Case 3History: This hypotensive patient has a gunshot wound to the left chest (Figure Q-3).Identical paper clips mark the entrance and exit wounds.

1. This radiograph is most likely [erect/supine] (PA/AP).2. Describe the major radiologic findings of the left hemithorax. _____________3. The mediastinum is [shifted right/shifted left/not shifted].4. Are proximal air bronchograms visible? _____________ What does this tell you?

_____________5. The police tell us that he was shot from the front. Is the entry wound midline or

left-sided? (Remember, they are identical paper clips.) _____________6. Diagnosis: _____________

FIGURE Q-3


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Case 31. supine (AP)—patient is hypotensive2. The left hemithorax is opaque laterally. The partially aerated lung is visible medially.3. shifted right (contralateral side)4. Yes. The air bronchogram on the left tells us that the major airways are open.

There is no central endobronchial obstruction, and the surrounding lung is almostairless (water density).

5. Left-sided. This is an AP supine film, so the anterior clip would be magnified. Becauseidentical paper clips were used, the bullet must have entered the left chest (magnifiedclip) and exited in the midline.

6. Diagnosis: Left hemothorax from gunshot wound. Relaxation atelectasis. Increasedpressure in left hemithorax causing contralateral mediastinal shift.

“Why shouldn’t truth be stranger than fiction? Fiction has to be believable.”—Mark Twain

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Case 4History: This middle-aged man was admitted to the ICU with fever, chills, and a white bloodcell count of 19,000/mm3.Figure Q-4A was obtained shortly after admission. There is a drain in the right pleural spacelaterally.

1. A indicates a _____________ catheter in [satisfactory/unsatisfactory] position.2. B indicates an _____________ tube in [satisfactory/unsatisfactory] position.3. Describe the lung abnormalities. _____________4. Diagnosis: _____________5. Several hours later, he became more short of breath. Figure Q-4B shows what

additional finding? _____________



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Case 41. central venous pressure catheter; satisfactory2. endotracheal tube; unsatisfactory (too high)3. Bilateral dense consolidation, air bronchograms, silhouette signs of diaphragms,

blunt right costophrenic angle.4. Diagnosis: Pneumonia.5. Tension pneumothorax on right—air in pleural space, low right diaphragm, heart

shifted to the left.

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Case 5History: This is a 50-year-old woman with pain on inspiration.Figure Q-5A is a baseline image obtained 10 months earlier. Figure Q-5B is the currentimage.

1. In Figure Q-5A, the [right/left] lung is more radiolucent. Explain the discrepancy._____________

2. Ten months later, there have been striking changes (Figure Q-5B). The cardiac size (cardiac silhouette) is _____________, whereas the pulmonary vessels [showcephalization/are normal]. [The right/The left/Both] costophrenic angle(s) is(are)blunted.

3. Diagnosis: Combining the history and your radiographic observations, the currentimage shows _____________ and _____________, most likely caused by _____________.

FIGURE Q-5 A

FIGURE Q-5 B

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Case 51. The left lung is more lucent. There has been a left mastectomy. The breast is miss-

ing, and there are clips in the axilla. There is less soft tissue on the left, so there isless absorption of radiation.

2. enlarged; are normal. The right costophrenic angle is blunt and there is a smallmeniscus. The right diaphragm also has changed shape (subpulmonic effusion).

3. Diagnosis: Pericardial effusion and right pleural effusion caused by metastatic breastcancer.

“I like only two kinds of men: domestic and imported.”—Mae West“She may be good for nothing, but she’s not bad for nothing.”—Mae West

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Case 6History: This is a young man without symptoms (Figures Q-6A and Q-6B).

1. There is a strange cardiomediastinal shape on the [right/left]. It causes a silhouettesign of what three cardiovascular structures? _____________, _____________, and_____________

2. Is there an abnormality visible on the lateral film? _____________3. Allowing for some overlap, there is a mass predominantly in the [anterior/middle/

posterior] mediastinal compartment.4. Diagnosis: Formulate a differential diagnosis. _____________

FIGURE Q-6 AFIGURE Q-6 B


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Case 61. left. left atrium, pulmonary artery, and aortic arch (knob) (left upper mediastinum).2. Density in retrosternal clear space, between sternum and trachea.3. anterior and middle. This is a large anterior and middle mediastinal mass on the left.

The lateral radiograph shows the mass predominantly in the anterior mediastinum.The silhouette sign indicates anterior mediastinum (left atrium) and middle medi-astinum (pulmonary artery, aortic knob).

4. Diagnosis: Remember the “5 T’s”:Thyroid. This mass is too low.Thoracic aortic aneurysm. The ascending thoracic aorta is on the right and looks normal

(i.e., not aortic aneurysm).Terrible lymphoma. This is usually lobulated and bilateral.Thymoma and Teratoma are the best choices. (Large masses commonly cross mediastinal

boundaries.) This was a thymoma.

“If law school is so hard to get through, how come there are so manylawyers?”—Calvin Trillin“Health food makes me sick.”—Calvin Trillin

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Case 7History: These are two older women, both with a cough (Figures Q-7A and Q-7B).

1. Both women have [interstitial/alveolar] consolidation of the _____________ lobe.2. What forms the sharp lower edges of their lesions? _____________ Reason for sharp

edge? _____________3. Patient [A/B] has a right hilar mass as well.4. Patient [A/B] has a right pleural effusion.5. Patient [A/B] has consolidation as a result of a central obstruction. How did you

know? _____________6. Diagnosis: Patient [A/B] has a lung cancer.



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Case 71. alveolar consolidation—right upper lobe2. The minor fissure is the sharp lower border. The upper lobe is consolidated, and the

middle lobe is well aerated.3. A4. A5. A. There is no air bronchogram.6. Diagnosis: Patient A has a carcinoma obstructing the right upper lobe bronchus

(i.e., no right upper lobe air bronchogram) and a hilar mass and effusion. Patient Bhas alveolar infiltrate or airspace consolidation with patent airways as a result of acommunity-acquired pneumonia.

“An onion can make people cry but there’s never been a vegetable that can makepeople laugh.”—Will Rogers“We are all here for a spell; get all the good laughs you can.”—Will Rogers

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Case 8History: This is a 60-year-old patient with increasing shortness of breath over several days(Figures Q-8A and Q-8B). His file contains an x-ray done 6 months earlier, when he wasasymptomatic (Figure Q-8C).

1. What has happened to the heart size in the 6-month interval? _____________2. What has happened to the pulmonary vessels? _____________3. How do the costophrenic angles compare? _____________4. What accounts for the right mid lung densities? _____________5. Diagnosis: _____________

FIGURE Q-8 A

FIGURE Q-8 C

FIGURE Q-8 B


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Case 81. The heart is bigger.2. The pulmonary vessels are bigger and slightly less sharp as a result of interstitial

edema.3. There is fluid in the right costophrenic angle.4. Fluid trapped in the major and minor fissures (pseudotumors). Figure Q-8B shows

the markedly thickened fissures.5. Diagnosis: The patient is in left heart failure (congestive heart failure).

“One day my father took me aside and left me there.”—John Vernor

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Case 9History: This is an older man with shortness of breath. Figures Q-9A and Q-9B are admis-sion x-rays.

1. What is the diagnosis on admission? _____________2. Two days later, the patient developed increasing dyspnea. In Figure Q-9C, how have

the lungs changed? _____________3. Diagnosis: _____________

FIGURE Q-9 A

FIGURE Q-9 C

FIGURE Q-9 B


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Case 91. Emphysema (chronic obstructive pulmonary disease). Hyperinflated, sparse upper

lobe markings.2. Left diaphragm silhouette sign, dense retrocardiac area, elevated left diaphragm

(compare position of stomach bubble).3. Diagnosis: Left lower lobe consolidation—most likely atelectasis. Pneumonia probably

would take longer to develop.

“He’s crazy; he thinks he’s a chicken.” “Why don’t you take him to a psychia-trist?” “I can’t, we need the eggs.”—Woody Allen“Schizophrenia beats dining alone.”—Oscar Levant

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Case 10History: This is an older man with cough for 4 months.1. In Figure Q-10A, there is an abnormality in or over the [right hilum/left hilum/

anterior mediastinum].2. In Figure Q-10B, this abnormality is seen _____________.3. Figures Q-10A and Q-10B show diaphragms are _____________. This indicates

_____________.4. Diagnosis: _____________

FIGURE Q-10 A

FIGURE Q-10 B


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Case 101. right hilum2. superimposed on the descending aorta. It is in the right lower lobe.3. low and flat. This indicates hyperinflation, probably chronic obstructive pulmonary

disease4. Diagnosis: Right lower lobe mass, probably cancer in a smoker

CT shows the mass adjacent to the right hilum

“If you do nothing, how do you know when you are finished?”—Anonymous

FIGURE Q-10 C

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FIGURE Q-11 AFIGURE Q-11 B


Case 11History: This is an older man from the cardiology clinic, complaining of dyspnea for daysand the sudden onset of chest discomfort and fever (Figures Q-11A and Q-11B).

1. The cardiac silhouette is _____________.2. The pulmonary vessels are _____________.3. Diagnosis: What is his cardiac diagnosis most likely? _____________4. Diagnosis: What explains his acute symptoms? _____________

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Case 111. large2. enlarged (cephalization) and mildly indistinct3. Diagnosis: mild left ventricular failure explains dyspnea for days.4. Diagnosis: Free air under the diaphragm (from perforated ulcer) explains sudden

chest discomfort and fever.

“There is nothing wrong with sobriety in moderation.”—John Ciardi

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Case 12History: The patient was described as follows (Figure Q-12): “Swimming lopsided and looks ill.”

1. The _____________ lung is consolidated.2. This is an [alveolar/interstitial] pattern.3. The patient swam _____________ side down because _____________.4. The patient is a _____________.

FIGURE Q-12


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Case 121. left (compare with normally aerated right lung)2. alveolar (the left lung is airless [water density])3. left side down because the left lung is heavier than the right lung4. Trachemys scripta—terrapin (turtle)

Dr. Timothy T. Klostermeier of Wilmington, Ohio, nursed the sick turtle back tohealth with daily subcutaneous shots of tetracycline for 2 weeks. (Radiology1996;199:58; with permission.)This case validates the “purple cow” theory of education. If you understand“purple,” and you understand “cow,” you will recognize a purple cow the firsttime you see one.

“It’s not over ‘til it’s over.”—Lawrence A. Berra (Yogi Berra)“It’s over!”—Lawrence R. Goodman, M.D.You are done! For those looking for more unknown cases, board review cases,and a few other goodies, there is a CD in the back cover.

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INDEX

AAbdomen

gas-containing structures of, 38f, 39, 40f, 41on computed tomography, 62f, 63search pattern for, 40f, 41

Abscess, pulmonary, 215f, 216Accessory fissures, 80f, 81, 82f, 83Acini, 50f, 51, 134f, 135. See also AlveoliAcute alveolar disease. See Alveolar filling diseaseAdenopathy

hilar, 170f, 171, 172f, 173mediastinal, 164f, 165

Adhesive atelectasis, 131Air

in lung, 19, 20f, 21, 66f, 67, 86f, 87. See also Airbronchogram sign

pleural. See Pneumothoraxsubcutaneous, 186f, 187subpulmonic, 186f, 187under diaphragm, 54f, 55

Air bronchogram sign, 102–115absence of, 110f, 111, 113, 114f, 115definition of, 105, 106f, 107, 109in alveolar filling disease, 108f, 109, 143in left lower lobe collapse, 122f, 123in left lower lobe pneumonia, 106f, 107interpretation of, 112f, 113model analogue of, 106f, 107on computed tomography, 106f, 107through cardiac shadow, 110f, 111vs. silhouette sign, 106f, 107. See also

Silhouette signAir trapping, expiratory film for, 14f, 15Air-fluid level, 148f, 149

after lung removal, 188f, 189in hydropneumothorax, 188f, 189in pneumonia, 148f, 149

Alveolar edema, 202f, 203Alveolar filling disease, 50f, 51, 52f, 53, 136f, 137, 138f,

139acute, 145diffuse interstitial disease and, 144f, 145focal, 146f, 147lobar sites of. See Consolidationmultifocal, 144f, 145on computed tomography, 6f, 67, 136f, 137signs of, 142f, 143, 145, 153

Alveoli, 50f, 51, 52f, 53, 134f, 135air in, 66f, 67, 137edema of, 202f, 203filling of, 136f, 137. See also Alveolar filling

diseaseAneurysm, aortic arch, 166f, 167Anterior mediastinum, 160f, 161, 173. See also

Mediastinummass of, 162f, 163

Anteroposterior (AP) view, 2f, 3, 16f, 17Aorta

ascendingin left heart enlargement, 198f, 199in mediastinal search, 45, 45fin right upper lobe consolidation, 96f, 97on computed tomography, 58f, 59, 91, 91f,

156f, 157on lateral x-ray, 38f, 39, 90f, 91, 154f, 155,

194f, 195on normal x-ray, 36f, 37, 154f, 155

descendingin left heart enlargement, 198f, 199in left lower lobe consolidation, 95in mediastinal search, 45, 45fmediastinal location of, 166f, 167, 167fon computed tomography, 58f, 59, 91, 91f,

156f, 157on lateral x-ray, 90f, 91, 154f, 155, 194f, 195on normal x-ray, 154f, 155

post-traumatic pseudoaneurysm of, 170f, 171three-dimensional view of, 28f, 29

Aortic knob (arch)aneurysm of, 166f, 167in mediastinal search, 45, 45fon computed tomography, 26f, 27, 58f, 59, 90f, 91,

156f, 157on lateral x-ray, 38f, 39, 154f, 155, 194f, 195on normal x-ray, 36f, 37, 38f, 39

Apical lordotic position, 17Artifacts, 4f, 5Ascending aorta. See Aorta, ascendingAspiration, of abscess, 215f, 216

of pin, 84f, 85, 85fAtelectasis, 113, 229f, 230. See also Collapse

adhesive, 131bandlike, 130f, 131cicatricial, 130f, 131hypoventilation, 130f, 131mechanisms of, 131mediastinal shift and, 182f, 183obstructive

central, 126f, 127, 129, 129f, 131peripheral, 127

passive (relaxation), 129, 129fpostoperative, 128f, 129resorptive, 127structure shift in, 124f, 125, 182f, 183

Atrial septal defect, 200f, 201Atrium. See also Heart

left, 194f, 195, 199enlargement of, 196f, 197

right, 194f, 195Axial plane, 64f, 65, 68f, 69Azygos fissure, 80f, 81, 84f, 85Azygos lobe, 80f, 81

Note: Page numbers followed by f refer to figures.

237

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238 Index

BBarium swallow, 166f, 167Bleeding, mediastinal, 158f, 159, 170f, 171, 192f, 193Bone, 19

density of, 27, 87on computed tomography, 56f, 57, 62f, 63

Breast, 42f, 43postmastectomy absence of, 54f, 55

Bronchiectasis, 104f, 105, 105f, 112f, 113Bronchus (bronchi). See also specific lobes

air-filled. See Air bronchogram signcontrast-aided examination of, 103, 104f, 105dilation of, 104f, 105, 105f, 112f, 113focal air trapping in, 14f, 15obstruction of, 126f, 127, 128f, 129.

See also Collapseon computed tomography, 60f, 61, 102f, 103right main stem, 60f, 61tumor of, 110f, 111

Bronchus intermedius, 121, 121fBullae, 150f, 151Bullet, in pleural space, 174f, 175

CCalcification

aortic arch, 166f, 167in granulomatous infection, 148f, 149on oblique view, 6f, 7

Cancerlung. See Lung cancermetastatic, 190f, 191, 213f, 214

Cardiac cycle, magnetic resonance imaging of, 30f, 31Cardiac shadow, air bronchogram through, 110f, 111Cardiac silhouette, 197. See also HeartCardiothoracic ratio, 196f, 197Cardiovascular disease, 194–209. See also HeartCarina, 36f, 37, 38f, 39, 45, 45f

on computed tomography, 64f, 65Catheter, 4f, 5, 208f, 209Cavitary mass, 146f, 147, 148f, 149Central venous catheter, 4f, 5, 208f, 209Cephalization, 200f, 201Chronic obstructive pulmonary disease (COPD), 20f,

21, 150f, 151, 152f, 153. See also EmphysemaClavicle, 42f, 43Collapse, 116–134

air bronchogram and, 122f, 123bronchial obstruction and, 126f, 127, 128f, 129fibrosis and, 130f, 131hilar displacement and, 124f, 125hydrothorax and, 129, 129fleft lower lobe, 116f, 117, 122f, 123, 124f, 125, 128f, 129left lung, 116f, 117left upper lobe, 116f, 117, 120f, 121, 132f, 133lingula, 119, 120f, 121, 132f, 133mechanisms of, 126f, 127moving marker structures and, 122f, 123postoperative, 129, 129f, 132f, 133right lower lobe, 116f, 117, 119, 119f, 121, 121f, 128f,

129, 132f, 133right lung, 129, 129fright middle lobe, 116f, 117, 118f, 119, 121, 121f, 132f,

133right upper lobe, 116f, 117, 118f, 119, 119f, 126f, 127,

130f, 131signs of, 116f, 117, 121, 122f, 123, 124f, 125

Colondensity of, 86f, 87splenic flexure of, 40f, 41

Computed tomography, 22f, 23, 56–69air bronchogram sign on, 106f, 107aorta on, 58f, 59, 91, 91f, 156f, 157aortic arch on, 26f, 27, 58f, 59, 90f, 91, 156f, 157axial, 24f, 25bones on, 56f, 57, 62f, 63bronchi on, 102f, 103bronchiectasis on, 104f, 105, 105fbullae on, 150f, 151contrast media in, 26f, 27, 56f, 57coronal, 24f, 25densities on, 26f, 27, 34f, 35, 63emphysema on, 150f, 151, 152f, 153granuloma on, 148f, 149heart on, 156f, 157high-resolution, 62f, 63, 66f, 67honeycombing on, 140f, 141Hounsfield units for, 26f, 27, 34f, 35, 63hydrothorax on, 129, 129finterstitial thickening on, 136f, 137

linear, 136f, 137, 138f, 139nodular, 136f, 137, 138f, 139

Kerley B lines on, 204f, 205loculated pleural effusion on, 184f, 185lung cancer on, 28f, 29, 152f, 153, 231flungs on, 56f, 57, 60f, 61, 64f, 65lymph nodes on, 156f, 157major fissure on, 79, 79fmediastinal trauma on, 170f, 171mediastinum on, 25, 25f, 26f, 27, 56f, 57, 58f, 59,

156f, 157oblique, 22f, 26fpericardial effusion on, 207, 207fplanes for, 64f, 65, 68f, 69, 69fpleural air on, 186f, 187pleural effusion on, 178f, 179pneumothorax on, 186f, 187pulmonary vessels on, 28f, 29sagittal, 24f, 25scout view for, 56f, 57, 58f, 59superior vena cava on, 26f, 27thymic mass on, 162f, 163upper abdomen on, 62f, 63

Congestive heart failure. See Heart failureConsolidation. See also Alveolar filling disease

left lower lobe, 94f, 95left upper lobe, 96f, 97, 101, 144f, 145lingula, 92f, 93, 100f, 101, 110f, 111multifocal, 145right lower lobe, 94f, 95, 100f, 101, 114f, 115, 121,

121f, 142f, 143right middle lobe, 78f, 79, 92f, 93, 94f, 95, 100f, 101,

118f, 119right upper lobe, 68f, 69, 69f, 96f, 97, 118f, 119, 142f, 143

Contrast mediabronchial, 103, 104f, 105CT, 26f, 27, 56f, 57esophageal, 166f, 167

COPD. See Chronic obstructive pulmonary disease(COPD)

Coronal plane, 64f, 65, 69, 69fCostophrenic sulcus (angle), 36f, 37, 38f, 39, 174f, 175

shallow (blunt), 176f, 177, 179, 181, 181fCross-sectional imaging, 22f, 23–35. See also Computed

tomography; Magnetic resonance imaging;Ultrasonography

axial, 22f, 23coronal, 22f, 23oblique, 22f, 23sagittal, 22f, 23

CT. See Computed tomography

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Index 239

DDecubitus position

for effusion, 8f, 9for pneumothorax, 10f, 11left lateral, 8f, 9right lateral, 10f, 11, 16f, 17

Densitieson computed tomography, 26f, 27, 34f, 35on plain film, 27, 86f, 87, 88f, 89

Descending aorta. See Aorta, descendingDiaphragm, 2f, 8f, 9, 40f, 41, 92f, 93

atelectasis-related shift of, 125density of, 88f, 89free air under, 54f, 55height of, 12f, 13hyperinflation and, 150f, 151left, 36f, 37, 76f, 77, 88f, 89

elevated appearance of, 8f, 9on lateral view, 90f, 91silhouette sign and, 90f, 91, 98f, 99, 122f, 123

medial, silhouette sign and, 110f, 111on computed tomography, 62f, 63on lateral view, 90f, 91right, 38f, 39f, 88f, 89

on lateral view, 90f, 91silhouette sign and, 88f, 89, 90f, 91, 119, 119f

subpulmonic fluid and, 178f, 179, 180f, 181, 183

EEchocardiogram, 32f, 33

pericardial effusion on, 206f, 207Edema

alveolar, 202f, 203interstitial, 202f, 203

Effusionpericardial. See Pericardial effusionpleural. See Pleural effusion

Electrocardiogram lead, 208f, 209Emphysema, 20f, 21, 150f, 151, 152f, 153. See also

COPD (chronic obstructive pulmonary disease)Empyema, 32f, 33Endotracheal tube, 208f, 209Esophagram, 166f, 167Esophagus

feeding tube in, 167, 167fon computed tomography, 58f, 59, 156f, 157

Expiratory film, 12f, 13air trapping on, 14f, 15pneumothorax on, 17

Extrapleural space, 175, 190f, 191

FFat, 86f, 87

density of, 27, 86f, 87Feeding tube, 167, 167fFelson’s axioms, 210Fibrosis, pulmonary, 130f, 131Fissure(s)

accessory, 80f, 81, 82f, 83azygos, 80f, 81, 84f, 85inferior accessory, 80f, 81, 84f, 85interlobular, 70f, 71major (oblique), 72f, 73, 84f, 85

edge appearance of, 74f, 75fluid in, 74f, 75, 176f, 177, 184f, 185, 227f, 228in left upper lobe collapse, 120f, 121in right middle lobe collapse, 118f, 119in right middle lobe consolidation, 78f, 79

Fissure(s) (Continued)line appearance of, 74f, 75on computed tomography, 60f, 61, 79, 79fon lateral view, 76f, 77shift of, 116f, 117, 118f, 119, 120f, 121thickness of, 74f, 75

minor (horizontal), 74f, 75, 75f, 84f, 85downward slope of, 75fluid in, 184f, 185, 227f, 228in right lower lobe collapse, 121, 121fin right middle lobe collapse, 118f, 119, 121, 121fin right middle lobe consolidation, 78f, 79in right upper lobe collapse, 118f, 119on lateral view, 76f, 77shift of, 116f, 117, 118f, 119, 119f, 120f, 121

superior accessory, 80f, 81, 84f, 85Fluid

alveolar. See Alveolar filling diseasedensity of, 20f, 21fissural, 74f, 75, 176f, 177, 184f, 185, 227f, 228pericardial, 197, 206f, 207, 221f, 222pleural. See Pleural effusionsubpulmonic, 178f, 179, 180f, 181, 183

Fluoroscopy, 17Foreign body, aspiration of, 84f, 85, 85fFracture, rib, 190f, 191

GGas. See also Air

density of, 86f, 87in abdominal structures, 38f, 39, 40f, 41

Granuloma, 148f, 149Gravity, 178f, 179Grid, 18f, 19, 19fGunshot wound, 174f, 175, 217f, 218

HHeart, 36f, 37, 38f, 39, 45, 45f

density of, 86f, 87, 88f, 89enlargement of, 196f, 197, 198f, 199, 233f, 234lateral view of, 194f, 195left, 194f, 195

border bulge of, 196f, 197enlargement of, 196f, 197, 198f, 199, 233f, 234mediastinum relationship to, 154f, 155

left shift of, 116f, 117on computed tomography, 156f, 157right, 88f, 89, 194f, 195

enlargement of, 197, 198f, 199mediastinum relationship to, 154f, 155

shift of, 116f, 117, 125size of, 3, 11, 12f, 13, 196f, 197ultrasonography of, 32f, 33, 206f, 207

Heart failurecase study of, 227f, 228cephalization in, 200f, 201, 205edema with, 202f, 203, 205left, 200f, 201, 202f, 203, 227f, 228pleural effusion in, 203, 206f, 207pseudotumor in, 185supine view of, 204f, 205

Hemithorax, white, 136f, 137, 182f, 183Hemorrhage, mediastinal, 158f, 159, 170f, 171, 192f, 193Hemothorax, gunshot wound and, 217f, 218Hernia, hiatal, 166f, 167Hilum, 36f, 37, 38f, 39, 171

adenopathy of, 170f, 171displacement of, 125, 130f, 131

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240 Index

Hilum (Continued)left, 124f, 125right, 44f, 45, 124f, 125, 156f, 157

Honeycombing, 140f, 141Hounsfield units, 26f, 27, 34f, 35, 63Hydropneumothorax, 189Hydrothorax, 129, 129f. See also Pleural effusionHyperinflation, 150f, 151

compensatory, 125Hyperlucency, 150f, 151Hypoventilation atelectasis, 130f, 131

IInferior accessory fissure, 80f, 81, 84f, 85Inspiration, 11, 12f, 13Interlobular fissure, 70f, 71Interstitium, 50f, 51, 66f, 67, 134f, 135

acute disease of, 139, 141chronic disease of, 139diffuse disease of, 138f, 139, 140f, 141, 153

alveolar consolidation and, 67, 67f, 144f, 145edema of, 202f, 203focal disease of, 138f, 139on computed tomography, 66f, 67, 67fthickening of, 136f, 137, 138f, 139

Intrafissural effusion, 74f, 75, 176f, 177, 184f, 185, 227f,228

Intrapleural air. See Pneumothorax

KKerley B lines, 202f, 203, 204f, 205

LLateral decubitus position

left, 8f, 9right, 10f, 11, 16f, 17

Lateral view, 4f, 5aorta on, 38f, 39, 90f, 91, 154f, 155, 194f, 195diaphragm on, 90f, 91fissures on, 76f, 77heart on, 194f, 195mediastinum on, 160f, 161, 162f, 163“normal” silhouette sign on, 90f, 91of esophagram, 166f, 167pleural fluid on, 8f, 9, 176f, 177search pattern for, 48f, 49structures on, 36f, 37, 38f, 39

Left anterior oblique position, 7Left atrial appendage, 194f, 195, 197Left lateral decubitus position, 8f, 9, 178f, 179Left lower lobe, 72f, 73, 76f, 77, 92f, 93

bronchiectasis of, 105, 105fcollapse of, 116f, 117, 122f, 123, 124f, 125, 128f, 129consolidation in, 94f, 95on computed tomography, 62f, 63pneumonia of, 98f, 99, 106f, 107

Left upper lobe, 72f, 73, 76f, 77air bronchogram sign in, 108f, 109collapse of, 116f, 117, 120f, 121, 132f, 133consolidation in, 96f, 97, 101, 144f, 145

Linear artifact, 4f, 5Lingula, 76f, 77

collapse of, 119, 120f, 121, 132f, 133consolidation in, 92f, 93, 96f, 97, 100f, 101, 110f, 111

Liver, 40f, 41, 42f, 43density of, 88f, 89on computed tomography, 62f, 63

Lobes. See Left lower lobe; Left upper lobe; Lingula;Right lower lobe; Right middle lobe; Right upperlobe

Lordotic view, 17Lower lobes. See Left lower lobe; Right lower lobeLung(s)

abscess of, 215f, 216air in, 19, 20f, 21, 86f, 87. See also Air bronchogram

signalveoli of. See Alveoliatelectasis. See Atelectasisblackness of, 12f, 13, 14f, 15, 27bronchus of. See Bronchus (bronchi)collapse of. See Collapseconsolidation in. See Consolidationdensity of, 86f, 87fissures of. See Fissure(s)interstitium of. See Interstitiumlobes of. See Left lower lobe; Left upper lobe;

Lingula; Right lower lobe; Right middle lobe;Right upper lobe

mass of, 146f, 147. See also Lung cancercavitary, 146f, 147, 148f, 149fissural fluid simulation of, 184, 185fhilar, 170f, 171, 172f, 173, 231f, 232size of, 146f, 147 vs. nodule, 146f, 147

nodule of, 122f, 123metastatic, 213f, 214multiple, 136f, 137on computed tomography, 136f, 137, 138f, 139size of, 146f, 147 vs. nodule, 146f, 147

normal, 54f, 55search pattern for, 46f, 47, 47f, 48f, 49spot on, 146f, 147white, 136f, 137, 182f, 183

Lung cancer, 147, 152f, 153case study of, 225f, 226, 231f, 232on computed tomography, 28f, 29, 152f,

153, 231fLymph nodes

hilar, 170f, 171, 172f, 173mediastinal, 156f, 157, 164f, 165

Lymphoma, 172f, 173

MMagnetic resonance imaging, 22f, 23, 29

cardiac cycle on, 30f, 31contraindications to, 31gray scale of, 31mediastinum on, 30f, 31of neural tumor, 169, 169f

Magnification, 3Main stem bronchus, right, 156f, 157Major fissures. See Fissure(s), major (oblique)Mass

mediastinal. See Mediastinum, mass ofover spine, 168f, 169pulmonary, 146f, 147. See also Lung cancer

cavitary, 146f, 147, 148f, 149fissural fluid simulation of, 184, 185fhilar, 170f, 171, 172f, 173, 231f, 232size of, 146f, 147

thymic, 158f, 160, 162f, 163, 223f, 224Mastectomy, 54f, 55Mediastinum, 154–173

adenopathy of, 164f, 165anterior, 160f, 161, 162f, 163, 173borders of, 154f, 155

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Index 241

Mediastinum (Continued)compartments of, 160f, 161density of, 88f, 89five T’s of, 163, 173, 224hemorrhage in, 158f, 159, 170f, 171, 192f, 193lateral view of, 160f, 161, 162f, 163lymph nodes of, 156f, 157, 164f, 165magnetic resonance imaging of, 30f, 31mass of

anterior compartment, 162f, 163lateral view of, 162f, 163middle compartment, 160f, 161, 164f, 165, 167,

172f, 173posterior compartment, 168f, 169, 169fsilhouette sign and, 98f, 99, 160f, 161tracheal displacement by, 158f, 159, 160f, 161,

172f, 173middle, 160f, 161, 163, 164f, 165, 166f, 167, 173on computed tomography, 25, 25f, 26f, 27, 56f, 57,

58f, 59, 156f, 157posterior, 160f, 161, 168f, 169, 169f, 173search pattern for, 44f, 45, 45fshift of, 188f, 189trauma to, 170f, 171vascular structures of, 166f, 167, 168fwidening of

diffuse, 158f, 159, 163, 170f, 171, 192f, 193focal, 158f, 159, 163, 172f, 173

Meniscus, 176f, 177, 179Metal, density of, 20f, 21, 27, 86f, 87Metallic artifact, 4f, 5Metastasis

pulmonary, 213f, 214rib, 190f, 191

Minor fissures. See Fissure(s), minor (horizontal)Mitral valve stenosis, 201MRI. See Magnetic resonance imagingMultiple myeloma, 168f, 169Muscle, density of, 86f, 87

NNasogastric tube, 208f, 209Neural tumor, 169, 169fNodule(s). See also Mass

metastatic, 213f, 214multiple, 136f, 137on computed tomography, 136f, 137, 138f, 139right upper lobe, 122f, 123size of, 146f, 147

Normal chest x-ray, 37–61. See also specific structures

OOblique views, 6f, 7, 16f, 17Obstructive atelectasis

central, 126f, 127, 129, 129f, 131peripheral, 127

Obstructive pulmonary disease, chronic (COPD), 20f,21, 150f, 151, 152f, 153

PPajama snap, 4f, 5Parietal pleura, 71Passive (relaxation) atelectasis, 129, 129fPericardial effusion, 197, 206f, 207, 221f, 222Pericardium, on computed tomography, 59, 59fPhotons, 18f, 19, 19fPin, aspiration of, 84f, 85, 85f

Pleuramediastinal mass displacement of, 159on computed tomography, 59, 59fparietal, 71visceral, 60f, 61, 71

Pleural effusionair-fluid level with, 188f, 189case study of, 221f, 222encapsulated (loculated), 183, 184f, 185fissural, 74f, 75, 176f, 177, 184f, 185, 227f, 228in heart failure, 203, 206f, 207mediastinal shift and, 182f, 183on computed tomography, 178f, 179on lateral decubitus view, 8f, 9, 176f, 177on supine view, 182f, 183, 192f, 193on ultrasonography, 32f, 33shallow (blunt) costophrenic angle and, 176f, 177,

180f, 181, 181fsubpulmonic, 178f, 179, 180f, 181, 183white lung with, 182f, 183

Pleural space (cavity), 71, 174f, 175air in. See Pneumothoraxbullet in, 174f, 175fluid in. See Pleural effusion

Pneumonia, 79air-fluid level in, 148f, 149case study of, 219f, 220, 225f, 226left lower lobe, 98f, 99, 106f, 107right lower lobe, 100f, 101right middle lobe, 100f, 101silhouette sign and, 98f, 99, 100f, 101

Pneumothorax, 10f, 11air-fluid level with, 188f, 189lung collapse and, 122f, 123on decubitus film, 10f, 11on expiratory film, 17on supine view, 186f, 187, 192f, 193tension, 188f, 189, 219f, 220

Portable x-ray, 2f, 3, 204f, 205Posteroanterior (PA) view, 1, 2f, 3, 4f, 16f, 17

inspiratory vs. expiratory, 12f, 13, 14f, 15right anterior oblique position for, 6f, 7search pattern for, 41

abdomen, 40f, 41lungs, 46f, 47, 47f, 48f, 49mediastinum, 44f, 45, 45fthorax, 42f, 43

structures on, 36f, 37, 38f, 39Pseudoaneurysm, 170f, 171Pseudotumor, 184f, 185Pulmonary artery, 60f, 61, 102f, 103, 134f, 135

left, 154f, 155, 156f, 157main, 58f, 59, 156f, 157, 194f, 195on computed tomography, 28f, 29, 58f, 59right, 58f, 59, 154f, 155

Pulmonary fibrosis, collapse and, 130f, 131Pulmonary lobule, 50f, 51Pulmonary vein, 60f, 61, 102f, 103, 134f, 135

on computed tomography, 28f, 29

RRadiation, 18f, 19, 19fRadiation safety, 33Radiodense, 19, 27Radiolucent, 19, 27Retrosternal clear space, 150f, 151, 154f, 155Rib

anterior, 42f, 43fracture of, 190f, 191

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242 Index

Rib (Continued)metastasis to, 190f, 191on computed tomography, 62f, 63posterior, 42f, 43

Right anterior oblique position, 6f, 7, 16f, 17Right lateral decubitus position, 10f, 11, 16f, 17Right lower lobe, 73, 76f, 77, 92f, 93

air bronchogram sign in, 108f, 109collapse of, 116f, 117, 119, 119f, 121, 121f, 128f, 129,

132f, 133consolidation in, 88f, 89, 94f, 95, 100f, 101, 114f, 115,

142f, 143inferior accessory fissure of, 82f, 83pneumonia in, 100f, 101superior accessory fissure of, 82f, 83

Right middle lobe, 76f, 77collapse of, 116f, 117, 118f, 119, 121, 121f, 132f, 133consolidation in, 78f, 79, 92f, 93, 94f, 95, 96f, 97, 100f,

101, 118f, 119pneumonia in, 100f, 101

Right upper lobe, 76f, 77air bronchogram sign in, 108f, 109collapse of, 110f, 111, 116f, 117, 118f, 119, 119f, 126f,

127, 130f, 131consolidation in, 96f, 97, 118f, 119, 142f, 143nodule in, 122f, 123

SSafety, 33Sagittal plane, 64f, 65, 68f, 69Scapula, 42f, 43

on computed tomography, 62f, 63Scar, 148f, 149Scattered x-rays, 18f, 19Sharpness, 3Silhouette sign, 86–101

absence of, 143, 145alveolar filling disease/consolidation and, 92f, 93,

94f, 95, 96f, 97, 142f, 143, 145aorta and, 96f, 97definition of, 89left diaphragm and, 98f, 99left heart and, 92f, 93, 100f, 101medial diaphragm and, 110f, 111mediastinal mass and, 98f, 99, 160f, 161misleading, 98f, 99normal, 90f, 91, 98f, 99pneumonia and, 98f, 99, 100f, 101right diaphragm and, 100f, 101, 119, 119fright heart and, 94f, 95, 100f, 101underpenetrated film and, 98f, 99vs. air bronchogram sign, 106f, 107. See also Air

bronchogram signSoft tissue, density of, 20f, 21, 26f, 27, 86f, 87, 88f, 89Sonography. See UltrasonographySpine

mass over, 168f, 169on computed tomography, 62f, 63

Splenic flexure, 38f, 39, 40f, 41on computed tomography, 62f, 63

Stenosismitral, 201tracheal, 24f, 25

Sternumhyperinflation and, 150f, 151on computed tomography, 62f, 63

Stomach, 36f, 37, 40f, 42f, 43on computed tomography, 62f, 63

Stomach bubble, 36f, 37, 40f, 41Stomach bubble sign, 180f, 181, 181fStyrofoam cup x-ray, 148f, 149Subpulmonic effusion, 178f, 179, 180f, 181, 183.

See also Pleural effusionSuperior accessory fissure, 80f, 81, 84f, 85Superior vena cava, 154f, 155, 156f, 157, 194f, 195

catheter in, 4f, 5on computed tomography, 26f, 27, 58f, 59

Supine viewblood flow and, 201heart failure on, 204f, 205pleural effusion on, 182f, 183, 192f, 193pneumothorax on, 187, 192f, 193

TTen Axioms, 210Tension pneumothorax, 188f, 189, 219f, 220Terrapin, 235f, 236Thorax, search pattern for, 42f, 43Thymus

mass of, 158f, 160, 162f, 163, 223f, 224on computed tomography, 58f, 59

Tomography, 17computed. See Computed tomography

Trachea, 36f, 37, 38f, 39, 45, 45f, 156f, 157compression of, 158f, 159, 160f, 161density of, 88f, 89displacement of

left lung collapse and, 116f, 117mediastinal mass and, 158f, 159, 160f, 161, 172f, 173right upper lobe collapse and, 119f, 125, 130f, 131

on computed tomography, 58f, 59right wall of, 154f, 155stenosis of, 24f, 25three-dimensional view of, 29, 29f

Trauma, mediastinal, 170f, 171, 192f, 193Tube

endotracheal, 208f, 209feeding, 167, 167fnasogastric, 208f, 209

Tumormediastinal. See Mediastinum, mass ofmetastatic, 190f, 191, 213f, 214pulmonary. See Lung(s), mass of; Lung cancerthymic, 158f, 160, 162f, 163, 223f, 224vertebral destruction with, 168f, 169

Turtle, 235f, 236

UUlcer, perforation of, 233f, 234Ultrasonography, 22f, 23, 32f, 33

empyema on, 32f, 33pleural effusion on, 32f, 33subpulmonic effusion on, 178f, 179

Underpenetrated film, 98f, 99Upper lobes. See Left upper lobe; Right upper lobe

VVena cava, superior, 154f, 155, 156f, 157, 194f, 195

catheter in, 4f, 5on computed tomography, 26f, 27, 58f, 59

Ventricle. See also Heartleft, 194f, 195, 199

enlargement of, 198f, 199, 233f, 234on computed tomography, 58f, 59, 156f, 157

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Index 243

Ventricle (Continued)right, 194f, 195

on computed tomography, 58f, 59, 156f, 157Vertebral body

multiple myeloma of, 168f, 169on computed tomography, 62f, 63

View(s)anteroposterior (AP), 2f, 3, 16f, 17apical lordotic, 17decubitus, 8f, 9, 10f, 11, 16f, 17lateral, 4f, 5. See also Lateral viewoblique, 6f, 7, 16f, 17posteroanterior (PA), 1, 2f, 3, 4f, 16f, 17

inspiratory vs. expiratory, 12f, 13, 14f, 15right anterior oblique position for, 6f, 7search pattern for. See Viewing sequencestructures on, 36f, 37, 38f, 39

Viewing sequence, 41, 135abdomen, 40f, 41lungs, 46f, 47, 47f, 48f, 49mediastinum, 44f, 45, 45fthorax, 42f, 43

Visceral pleura, 60f, 61, 71Visceral pleural line, 186f, 187

WWater, density of, 27, 86f, 87Wheezing, 15White lung, 136f, 137, 182f, 183

XX-ray beam, 18f, 19, 19f

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Felson's Principles of Chest Roentgenology, Third Edition