Radiology Lecture 01

8/14/2019 Radiology Lecture 01

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Introduction to radiology

Lecture 1

Basic terms and definitions

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Radiology

In medicine, the discipline of medical science that useselectromagnetic radiation andultrasonics for the diagnosis andtreatment of injury and disease.

Radiology originated with thediscovery of X rays by Germanphysicist Wilhelm ConradRoentgen in 1895.

W.C. Roentgen was awarded thefirst Nobel Prize in physics (1901)for his work.

Wilhelm Conrad Roentgen

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What you need to know about imaging:

a. Understand thephysical basis ofimaging.

b. Recognize clinicalimages produced byvarious modalities.

c. Identify the advantagesand disadvantages ofvarious imagingmodalities.

d. Understand the termsused in differentimaging modalities.

a b

cd

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The most commonly used types of radiation are X-rays used in roentgenology

and gamma rays used in different modalities of nuclear medicine, X-rays andgamma rays are ionizing electromagnetic radiations with similar characteristics

differing only in their mechanism of production.

The third type which is used in medical imaging, relatively new in medical

imaging, is radiofrequency radiation. It is used in magnetic resonance Imaging,

which is also of the electromagnetic type but is non-ionizing. Infrared light used in thermography is another non-ionizing type of radiation.

Ultrasound is entirely different in nature being non-electromagnetic, and is

propagated through matter as mechanical vibrations.

Medical imaging of internal body structuresis achieved through the use of following

types of radiation:

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Imaging

modalities:1. Diagnostic roentgenology,

or conventional

roentgenology or X-rays.

2. Computed axial

Tomography (CAT).

3. Diagnostic Ultrasound(Ultrasonography, USI).

4. Magnetic Resonance

Imaging (MRI ).

5. Nuclear Medicine,

(radionuclid imaging ore

scintigraphy).

6. Thermography.

7. Interventional Radiology .

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2

3

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Imaging


or conventional


2. Computed axial

Tomography (CAT).



Imaging (MRI ).


(radionuclid imaging orescintigraphy).

6. Thermography.


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2

3

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Imaging


or conventional


2. Computed axial

Tomography (CAT).



Imaging (MRI ).



6. Thermography.


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2

3

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Imaging


or conventional


2. Computed axial

Tomography (CAT).



Imaging (MRI ).



6. Thermography.


1

2

3

4

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2

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Imaging


or conventional


2. Computed axial

Tomography (CAT).



Imaging (MRI ).



6. Thermography.


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2

3

4

5

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2

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Imaging


or conventional


2. Computed axial

Tomography (CAT).



Imaging (MRI ).



6. Thermography.


1

2

3

4

5

6

7

11

2

1


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Imaging


or conventional


2. Computed axial

Tomography (CAT).



Imaging (MRI ).



6. Thermography.


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2

3

4

5

6

7

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What is the damaging effect of

radiation? The ions formed then can go

on to react with other atomsin the cell, causing damage.

An example of this would beif a gamma ray passes througha cell, the water moleculesnear the DNA might beionized and the ions mightreact with the DNA causing itto break.

Charged atoms in the livingorganism could causedifferent type of damage forexample cancer induction orgenetic mutation!

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Effective dose

The effective dose of an examination is

calculated as weighted sum of the doses to

different body tissues.

The weighting factor for each tissue depends onits sensitivity

The effective dose thus provides a single dose

estimate related to the total radiation risk nomatter how the radiation dose is distributed

around the body.

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The effective doses

Procedure typical

effectivedose mSv

CXR

equivalents

Approx. equivalent period

of background radiation

X ray examinations

Limbs and joints 0.01 0.5 1.5 days

chest(pa) 0.02 1 3 days

abdomen 1 50 6 months

Lumbar spine 1.3 65 7 months

CT head 2.3 115 1 year

Barium meal 3 150 16 months

CT chest 8 400 3.6 yearsCT abdomen pelvis 10 500 4.5 years

Rradionuclide studies of

lung ventilation

0.3 15 7 weeks

lung perfusion 1 50 6 months

bone 6 300 2.7 years 16


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For a patient the protection lies in

the doctor's decision!

The decision to expose patientsto radiation must be made with

risks in mind!

So an examination should berequested only where clinical

benefits far outweigh the risks of

radiation sensitivity, cancer

induction, and genetic mutation!

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h f ll i h i l h


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The following physical phenomena are

the basis of modern imaging:

X ray examination

X-rays are absorbed in tissue.

X-rays, are based upon the fact that different tissues providedifferent degrees of X-rays attenuation.

The transmitted X-rays moving out of the patient, fall on thefluorescent screen or film make a image of body structures.

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Roentgenologic equipment

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Magnetic Resonance Imaging (MRI)

Magnetic resonance

imaging or tomography,

a form of medical

imaging that measures

the response of the

atomic nuclei of body

tissues to high-frequency

radio waves when placed

in a strong magnetic

field, and that produces

images of the internal

organs.

In a magnetic examination a patient on

the examination table is exposed to a

strong and very homogeneous

magnetic field. This static magneticfield changes the direction of all of the

spinning hydrogen nuclei in the body,

so that they are aligned parallel to the

direction of the field. Radio frequency

radiation is then applied to tissueswhere energy quanta are absorbed by

some of the protons, these become

excited as a result and while decaying

send quanta of emradiation to the

environment. These photons aredetectable and slice images are

reconstructed from the resultant

interference pattern.

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MRI equipment

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Ultrasound equipment

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Gamma camera

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Infrared Imaging or Thermography

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f


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Infrared detector

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l h d


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General schemes and terms

Sou

rceofradiation

X-rays

Gamma rays

Ultrasound

Radio waves

Infra red rays Objectofexamination

Chest

Head

GI

Hand

Legs

.

Registe

rofinformation

Detector

Film

Fluorescent

screen

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Source of radiation,

Object of examinationRegister (registrant) of information

Two types of systems


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Two types of systems

differ in source of radiation:

roentgenology

computed tomography

ultrasound imaging

the transmissionsystem - radiationtransmits through

the object

scintigraphy

computed emission

tomography Positron emission tomography

(PET)

the emissionsystem radiation

emits from theobject

transmission

radiopharmaceuticalsE

m

i

s

s

i

o

n

MRI

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T i i


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Transmission system

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T i i i


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Transmission system imagesComputer transmission tomography

images of chest with pneumonicinfiltration.

Plain film image of chest with

pneumonic infiltration.

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E i i t


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Emission system

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E i i t i


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Emission system images

Conventional liver AP and PAradionuclide planar images(scintigrams).

Dynamic radionuclide images.

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Two types of images differ in way ofpresentation

Panoramic imagingimaging of whole body

part, also called full-sizeimaging because the

anatomy is shown in itsoriginal size

Tomographic imaging

imaging of slice of some

body part

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Plain film


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Plain film

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3-dimensional object is projected into a 2-dimensional image

Shadows of different organs are summated on film

Tomogram


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Tomogram

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In tomographic imaging radiation is directed ore emitted onlyinto or from one thin disc or slice of tissues.

In final image there is no summation of tissues densities.


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In emission systems


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In emission systems

Plane AP emission radionuclideimage of abdomen

Axial, sagittal and coronal emissionradionuclide tomograms

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Panoramic images


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g

plain film in x-ray imaging

in radionuclide imaging

Two dimensional

REPRESENTATION(map or

shadowgraph) of

three dimensional

object (whole

body part: chest,abdomen, hand,

head)

it needs

multiple

views -

projection:

Anterior-posterior(AP) ore posterior-anterior (PA)

Lateral (from theside)

Oblique (diagonally)

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Plain film of the head in direct and lateral


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Plain film of the head in direct and lateral

views

posterior anterior lateral41

Plain film of the chest in direct and lateral


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Plain film of the chest in direct and lateral

views

posterior-anterior lateral42

Radionuclide imaging of the abdomen


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Radionuclide imaging of the abdomen

in direct and lateral views

posterior anterior lateral43


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Tomography imaging of slice of some body part

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Tomogram orientation


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Tomogram orientation

Coronal parallel withthe plane of front

Transverse or axial

perpendicular to the

main axis of the body

Sagittal parallel with

the main axis of the

body

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Tomographic methods


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MRI CAT PET USI

Tomographic methods

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Analogue Digital


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g g

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Analogue techniques Digital techniques


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Analogueradiography

Analogue

Fluoroscopy

Analogue

Traditional

Tomography

Computedtomography

Ultrasonography

Magneticresonance imaging

Digital radiography

Isotope imaging

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Resolution


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Resolution

A measure of the ability of an imaging system toseparate the images of closely adjacent objects.

It is also the smallest area identified as a

separate unit. Spatial resolution may have to be represented

as points or distance between sample points.

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Spatial resolution


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Contrast resolution or contrast of image


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Smallest difference in color intensity which canbe detected on image

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Do you remember what do these terms mean?


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Do you remember what do these terms mean?

Radiology X-rays, CAT, USI, MRI, Nuclear

Medicine, Thermography,

Ionizing and non ionizing

radiation Transmission and emission

systems

Planar and tomographic

images

Projection Tomography

Coronal

Axial

Sagittal Analogue

Digital

Spatial and contrast

resolution

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A diagnostic image is composed of differences in contrast

between tissues which result from differences in radiation


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between tissues which result from differences in radiation

interaction in the tissues

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The thickness of thetissue affects the

attenuation of the x-rays.


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The tissue typeaffects the the

attenuation of the x-

ray

The five densities can be3

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differentiated on film

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2

3

4

1. Metal

2. Bone

3. Soft tissue

(water)

4. Fat

5. Gas

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5

Radiographs are summation shadows created by

differences in contrast between tissues Tissue thickness


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differences in contrast between tissues. Tissue thickness

and tissue composition affect the attenuation and

therefore, the shade(s) of gray in the final shadow image.

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Two projections are necessary!

F t f th di t l d f th di (C ll ' f t )


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Fracture of the distal end of the radius (Colle's fractures).

lateral viewthe angulation in a

dorsal direction

v = volarly, d = dorsally

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AP view shortening or compressionthe distal end of the radius

Two projections (views)


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61 Lateral PA

Depending on information detector, and

th f t hi ( l ti f )


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the way of watching (real time ore frozen)

Digitalfluoroscopy

Fluoroscopy

Digitalradiography

Conventionalradiography

FilmElectron

detector, PCscreen

Electrondetector, PC

screen,dynamic

images in real

time

Fluorescentscreen,

dynamicimages in real

time

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Fluoroscopy - view in real time


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Positive view on

screen

X-ray tube Fluorescent screen

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Fluoroscopy used in diagnose different motordisorders of GI organs


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Oesophagus movement during oesophagoscopy

at patient with achalasia64

FLUOROGRAPHY


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- photography in which the

image is formed byfluorescence.

- widely used in

prophylactic

examinations,

- used to prevent disease

such as tuberculosis and

lung cancer.

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Positive


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Negative

Inversion

opposite or contrary in position, direction, order, or effect

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ROENTGENOGRAPHY

Plain film roentgenogram - negative view to fluoroscopy


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screen view

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Screen positive Film - negative

Special terms used on x-ray reports(we usually describe a negative film that is why)


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Radiopaque (light or white).

Synonym: High density.

Radiolucent (dark or black).Synonym: Low density.

Water density (middledensity)

PA view of normal chest 69


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Remember in film:Black = air-filledWhite = bone, calcium,fluid, pus, blood, collapse

Gray = soft tissues andsolid organs

How to Approach Reading any

Image


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Image

Identify the patient When was the image taken

Are these the proper images:

Correct type of study

Correct / complete views

Correct limb Contrast

The five densities

Are the images technically adequate

Why did you order the image

What did you expect to see

Do you see it

Now start over fresh

POSITIONING FOR XRAYS


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For the FRONTAL plane, werefer to the direction that

the XRay beam goes through

the patient. Thus a

POSTERIOR-ANTERIOR (PA)

chest is done with the XRaysentering the patient's back

(posterior) and passing

through to the front

(anterior) where they strikethe detector (film or charged

plate).

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The frontal chest film


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Ascending

aorta

Aortic knob

Descending

aorta

RALA

RVLV

View the film asthough the patient is

facing you with his

left on your right

If the film isunmarked,

remember your

anatomy (heart and

aortic arch are left

of midline)

A lateral chest XRay


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Here the XRays strikethe patient's right side,

pass through her, and

strike the detector at

her left. The 'skirt' she is wearing

is made of lead to

protect her ovaries from

the radiation.

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Normal lateral filmTypically left chest is placed againstdetector to minimize cardiac

magnification


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E

TDA

LA

RV

LV

Thoracic Imaging Strategies

A h i i i


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Approach to image interpretation

What is the expected normal and variantanatomy?

Is something absent?

Is there some additional structure present?

Look at the bones and soft tissues

Look at the heart and mediastinum

Look at the lungs and pleura

Look at the airways Look at the diaphragms and upper abdomen

Look at the bones

Examine scapulae, humeri,


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The location of an abnormal

shadow can be described byits proximity to a particular rib

or interspace

Identify the 1st rib by its

anterior junction with the

manubrium then count downthe posterior ribs

12

p , ,

shoulder joints, clavicles, ribs

and spine for symmetry


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Note the multiple right and left sided rib fractures.

Healing fracture

Survey, look carefully and thoroughly at thesoft tissues


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Breast tissues (if applicable)

SkinSupraclavicular areas

Axillae

Subcutaneous fat

Muscles Which film is that of a woman?

What happened


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Notice the asymmetry of the

left breast shadow relative

to the right and the surgical

clips in the left axilla

Diagnosis: Leftbreast cancer

treated with

lumpectomy and

axillary nodedissection

pp

to this patient?

Look at the diaphragm and upper abdomen


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The diaphragm is amusculotendinous sheet

separating the thoracic and

abdominal cavities

The left and right

hemidiaphragms are

usually well seen on PA

and lateral films

The plane of the rightdiaphragmatic dome is usually

about half an interspace higher

than the left

R

L

L

R

~ interspace

Left phrenic nerve paralysis


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The left hemidiaphragm is elevated and demonstrates paradoxical motion with

inspiration consistent with paralysis of the phrenic nerve.

Look at the mediastinum look at right paratracheal stripe and hilar contours to evaluate for lymphadenopathy

look at paraspinal lines, anterior clear space, and the spine to evaluate for a mediastinal


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mass

A P

Look at the heart


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The plain film diagnosis of heart disease is limited to determining:

Cardiac enlargement

Pulmonary vascular abnormalities

Congestive failure

The width of the adult heart should be < half

the greatest thoracic diameter, measured

from inside the rib cage at its widest point

near the level of the

NORMAL

Mitral valve

replacement from

rheumatic heart


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rheumatic heart

disease

Mitral valve replacement LA enlargement secondary

to long-standing MV

stenosis and regurgitation

a complication of a

streptococcal infection

resulting in mitral valve

dysfunction over time

Treated with valve

replacement

The frontal film

Pleura not normally

visible


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Pulmonary artery

Blood-filled pulmonary

vessels cast soft gray

shadow and typically

taper out to periphery,while bronchi and

bronchioles are air filled

and do not cast a shadow

on the image

visible

The frontal film


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Trachea

R mainbronchus

L mainbronchus

Gastric air bubble

bronchi and bronchioles

are air filled and do not

cast a shadow on the

image

Airways bronchogram with contrast

in airways


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THESE ARE NOT DONE ANY MORE

AIRWAYS CT CORONAL RECONSTRUCTION

which replaces contrast bronchography


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Pneumothorax


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Take note of the

resultant low X-rayattenuation (black)

where the airways have

collapsed

Tension

pneumothorax: theleft lung has

collapsed completely

The non-aerated lung

is significantly

diminished in size

Air is seen in the pleuralspace. Notice the air in the

costophrenic sulcus when the

patient is supine for CT.

Pneumothorax where the airgoes depends on positioning


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Centrilobular emphysema


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Hyperinflated lungs, paucity of upper lung vessels, crowding of lower

vasculature, and flattened diaphragms are seen in emphysema

Status post pneumonectomy with shift ofheart/mediastinum to the left


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Clips at

bronchial

stump

The stomach bubbleAir may be present in


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the stomach and can

be seen on PA andlateral chest films

Air, being less dense

than fluid, will rise and

can be seen in thefundus of the stomach

on plain film provided

the patient is uprightIn the lateral chest film,

the presence of the air

bubble close under one

diaphragmatic shadow

determines which is the

left hemidiaphragm

L

R


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How an upright posteroanterior chest

X-ray is taken Images are usually is taken oninspiration, with the patient standing

in front of film cassette (1)

chest and X-ray tube (2) about six

f b hi d hi


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feet behind him.

The PA position places the heart andupper mediastinum closer to the film

with greater distance to the exposing

Xray tube (generally 72 inches)

making the Xrays more parallel as

they enter the body and avoidingdisproportional enlargement of

anterior vs. posterior structures.

The upper lung arterial vessels in

upright posture, being well above

cardiac chamber level, are usually

much less prominent than the lower

lobe vessels which are at or below

cardiac chamber level.

1 2

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R

A

L

A

R

V L

V


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Normal pa and ap film


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On a supine frontal Xray of the chest there are significant differences in

the appearance of normal pulmonary vasculature and mediastinum.The closer distance of the exposing Xray tube (often only 40 inches from

the film cassette) makes the Xrays more diverging and disproportionally

enlarges the appearance of structures that are farther from the film (the

anterior body structures such as the ascending aorta).

Major fissure

Two films at right angles to one another are needed todetermine the true location of any foreign body or

mass within the thorax


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Granuloma within the RML

RML

The nodule is in

the RML and

calcified

Natural roentgen contrast of the abdomenorgans is bad


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The pathological tissue whichhas almost the same density as

the adjacent structures cannot

be seen on plain film.

You can see:1.Gas in rectum/sigmoid

2.Gas in ascending and

descending colon

3.Bones

Artificial contrast is needed tocreate density difference.

3

3

22

1

100

Please write down in

your paper the name of


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structures in picturewith letters

Now correct yourself

X ray Imaging without contrast media is suitable

for the examination of bones and organs


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for the examination of bones and organs

containing gas (like the lungs), but soft tissuescannot be separated from one another.

Liver and kidney for instance, as well as brain and

cerebrospinal fluid are equally grey in aradiograph.

For the visualization of soft tissues contrast media

and/or digital methods with a computer must be

used.

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X ray Imaging without contrast media

PNEUMOPERITONEUM


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PNEUMOPERITONEUM

Upright

Nondependent point


PNEUMOPERITONEUM


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Supine Double Bowel Wall Sign

PNEUMOPERITONEUM

Outlining of liver/GB

ion

Calcified structures (WHITE BITS)


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Calcified structures ( WHITE BITS )

Calcification can be broadly divided into 3 types: (1) Calcium that is an abnormal structure - eg. gallstones

and renal calculi

(2) Calcium that is within a normal structure, but representspathology - eg. nephrocalcinosis,

(3) Calcium that is within a normal structure, but is harmless- eg. lymph node calcification.

Bones are normal white structures. On the AXR they comprisemainly those of the thoraco-lumbar spine and pelvis. Findings arelargely incidental as direct bone pathology would be investigated

with specific views.


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Gallstones

X ray Imaging without contrast media35 year old with recurrent abdominal

pain:


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pain:Extensive pancreatic

calcification = recurrent

pancreatitis

X ray Imaging without contrast mediaThis patient was admitted with poor renal

function.


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Nephrocalcinosis Causes of

Nephrocalcinosis include:

Hyperparathyroidism

Medullary sponge

kidney



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35 year old with bloody

diarrhea

Thumb-printing transverse

colon = Colitis

X ray Imaging without contrast mediaBowel obstruction


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Intra-luminal Gas: Low Small Bowel

Obstruction

SBO

Plain abdominal radiograph


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Plain abdominal radiograph.

Multiple dilated loops of small bowel within

the central abdomen. Gas is not seen in the

large bowel. No evidence of hernia or

gallstone to suggest potential cause of the

dilated loops.

These findings are in keep with a low small

bowel obstruction.

I would like to know if the patient has a

history of abdominal surgery as the

commonest cause is surgical adhesions.

Large bowel obstruction


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Haustra visible do notcross lumen

Localised around outside of

film Small bowel may also be

dilated depending on

competence of ileocaecal

valve

Contrast agents

Administered material used to see structures or


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Positive contrast media - attenuate X-rays greaterthan the soft tissues of the body: Barium sulfate into the GI tract; Iodine compounds into the vessel.

Negative contrast media - attenuate X-rays less thanthe soft tissues of the body:

Air, Carbon dioxide and other gases.

pathologic processes that would not be seenotherwise.

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Contrast agents

Positive contrast media - attenuateX-rays greater than the soft tissues

Negative contrast media - attenuateX-rays less than the soft tissues of


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of the body: Barium sulfate into theGI tract; Iodine compounds intothe vessel.

the body: Air, Carbon dioxide andother gases.

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Upper gastrointestinal tract study,GI examination, upper GI series

Uses in following clinicalproblems:

Normal AP supine view of the abdomen


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Diseases and injuries of

esophagus, dysphagia.

Stomach and duodenum in

complex with Endoscopy

examination.

following the oral administration of barium

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Barium enemaUses in following clinical

problems:AP view of abdomen with barium

instilled retrograde into the colon

under fluoroscopic control


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Diseases and injuries of

colon in complex with

Endoscopy examination

under fluoroscopic control.

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Intravenous pyelography(intravenous urography IVP)

Iodine compound (contrast) Normal IVP
http://kobiljak.msu.edu/WebGraphics/Radiology/Slide_Set_1/Slide19.jpg


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is injected intravenously andfiltered and excreted by thekidneys.

Contrast medium in bilateralrenal collecting system with

increased density. Contrast agent may be

instilled intravenously oreinto urethra, so calledretrograde cysto- or

urography

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Intravenous pyelography

This method show an

anatomy and physiology ofRight sided hydronephrosis on PA

abdomen film
http://kobiljak.msu.edu/WebGraphics/Radiology/Slide_Set_1/Slide18.jpg


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urinary system by time offiltration and excretion of

contrast media, and

visualization of all structures

of system.

abdomen film

Uses in complex with CAT and

nuclear medicine for evaluate

urethral calculus, hematuria,

infections, renal trauma,

hydronephrosis, renal tumor

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Angiography

Normal angiographic image ofcoronal vessels

Normal angiographic image ofabdominal vessels


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Endoscopic retrogradecholangiopancreatography (ERCP)

ERCP is used primarily to

diagnose and treat conditions


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of the bile ducts, including

gallstones, inflammatory

strictures (scars), leaks (from

trauma and surgery), and

cancer.

Through the endoscope, the

physician can see the inside of

the stomach and duodenum,

and inject dyes into the ductsin the biliary tree and pancreas.

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Endoscopic retrogradecholangiopancreatography (ERCP)

ERCP, CBD StonesERCP, CBD multiple Stones


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Radiography (roentgenology) (X-rays)

Radiographic studies include all procedures


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using X-rays

plain film X-rays,

fluoroscopy,

photofluorography,

angiography, urography

conventional tomography

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Advantages

Cheap

Rapid

Panoramic view

Good spatial

resolution

Disadvantages

Ionizing radiation

Superimposition-

summation ofshadows

Bad contrast

resolution

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Radiology Lecture 01