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INTRODUCTION TO RADIOLOGY
Casey Sams, MD
Introduction to Radiology
I: Radiology Who we are What we do Our tools How can you help us help you
II: Contrast III: Plain Film Imaging of the Abdomen IV: Radiology at UNC V: Parting Thoughts
Definition of Radiology
Radiology is a medical specialty using medical imaging technologies to diagnose and treat patients.
So what does this mean?
We do NOT spend all day in a small dark room staring at a computer screen
….just most of the day
A widely varied discipline
Read a chest x ray Stage lymphoma Do a TIPS procedure Do a biopsy (lung, bone, thyroid,
breast…) Inject a joint Do a barium swallow
With multiple subspecialties
Breast Body Neuro MSK Peds IR
What our are tools?
X-rays CT MRI Ultrasound Nuc Medicine Fluoroscopy Mammography
Conventional Radiography “X-Ray” Lingo:
Density Opacity
Observable Densities: Metal Bone Soft Tissue Gas
Computed Tomography (CT) Lingo:
Attenuation Density Enhancement
Hounsfield Units -1000 air *** -100 fat 0 water *** 20-80 soft tissues 100’s bone/Ca/contrast >1000’s metal
Large radiation dose
Nuclear Medicine (NM) Lingo:
Counts or Activity
Physiologic imaging Radionuclides
(Technetium) Radiopharmaceuticals
(Choletec) Radioactivity stays with
the patient until cleared or decayed
Ultrasound
Lingo Echogenicity Shadowing Doppler for flow
No radiation Can be portable Relatively
inexpensive
Magnetic Resonance Imaging (MRI) Lingo:
Signal intensity T1 T2 Enhancement
No radiation Strong magnetic field
No pacemakers No electronic implants
Small, loud tube Patients must hold still Relatively expensive
Fluoroscopy
Lingo Filling defect Density Opacity
Real time information Radiation dose
dependent on length of exam
http://www.med-ed.virginia.edu/courses/rad/gi/index.html
Mammography
Lingo Microcalcifications Mass Asymmetric density
Screening exam consisting of 2 views recommended yearly for women over 50
We still recommend it!
http://www.mdgrant.com/images/NormalMammogram.jpg
When will you interact with Radiology? Anytime you read a report on a study As a part of rounds (critical care and ID
rotations in particular) When we call you up to ask about more
information before we do a study When you call us to ask about which
study should be done
And if you want more…
Rad 401 elective is a great way to get a broad introduction to radiology. Very helpful for people not interested in pursuing a career in radiology (plus those who are!)
Pediatric radiology rotation Neuroradiology rotation Choose your own adventure….
How can you help us help you? Indication, indication, indication How will this study impact your clinical
decision making? If it won’t, perhaps its useful to rethink the need for the study.
Become adept at how to read basic studies (chest and abdominal films for line and tube placement in particular)
Why is indication so important? It provides a paradigm for the picture we
are reading. More information will help tailor the
report to your clinical question. Depending on the indication, the hospital
may not be reimbursed for the study
GOOD BADdyspnea in cancer patient
R/O PE
abdominal pain in Crohn’s patient s/p SB resection
R/O pain
Pain over dorsal aspect of hand
trauma
Contrast
Oral contrast is frequently used in CT of the abdomen and pelvis and is very safe
There are 2 types of intravenous contrast. Iodinated contrast for CT Gadolinium based contrast for MRI
Radiologists like contrast !! BUTContrast is not without risks
Allergic Reactions to iodinated contrast Can range from mild to severe (hives to
anaphylaxis) If mild allergic reaction, can pretreat
with prednisone (50mg administered 13, 7, and 1 h prior to scan + Benadryl 1 hour before the scan)
If severe allergic reaction, contrast is contraindicated!
Iodinated contrast and renal failure
Contraindicated in renal failure (acute and chronic) because of risk of contrast induced nephropathy (CIN); Strict UNC cut off is Cr of 1.8.
Avoiding contrast in the setting of acute renal failure is important, but it is difficult for the radiologist, because the creatinine may be normal. (ie <1.8)
In hyper-acute renal failure, the creatinine hasn’t risen yet. Decreased urine output or anuria is acute renal failure – regardless of the creatinine.
Remember; first do no harm! Non-contrast studies can often be quite helpful.
MR Contrast and NSF
Risk of nephrogenic sclerosing fibrosis (NSF) increases with decreasing GFR; contraindicated <30
Progressive fibrosis of skin in patients with renal failure (typically on dialysis) which result in painful contractures and, possibly, death.
http://jama.ama-assn.org/content/vol297/issue3/images/medium/jmn60162fa.jpg
Reading an abdominal film
Where can you look at images PACS workstations
ED ICUs
WebCIS based PACS (java script) Web Based PACS
Basics:Looking at Imaging Studies:
Adequate Study? Correctly labeled with patient’s name, MR#, and
the date of the study? Technically adequate?
Systematic versus Focused look at a study: Radiologist does both! As the requesting clinician, you should also look at
your patient’s study (at least plain films), as well as follow up on the final report. PTX, PNA, pleural effusions, SBO, free air Evaluate lines and tubes (especially the ones you
placed!)
Several different type of abdominal film series
KUB (kidneys, ureter, bladder) 2 View---AP supine and erect abdomen Acute abdomen series: 2 view with
upright chest Lateral decubitus (Left or Right) Cross table lateral---prone or supine
Systematic process• Lines and tube (enteric tube, feeding tube, foley catheter, rectal tube, fem lines)• Bowel gas pattern (dilated loops, air where it shouldn’t be)• Visceral contours (hepatomegaly, abnormal soft tissue mass)•Abnormal calcifications (gallstones, kidney stones)• Bones
Enteric tube (NG/OG) placement Tip AND sidehole need to be within the
stomach body for proper suction
REALLY BAD – enteric tube in lung
http://icvts.ctsnetjournals.org/content/vol4/issue5/images/large/429fig1.jpeg
Small Bowel Obstruction (SBO) Gasless abdomen if bowel loops are fluid
filled Dilated small bowel loops (>3cm) Sometimes difficult to differentiate
between SBO and ileus (both colon and small bowel tend to be dilated)
http://archive.student.bmj.com/issues/02/04/education/102.php
Paucity of gas
CT correlate: SBO
Dilated loops of small bowel
CT correlate: more gas, & SBO
Pneumoperitoneum
Pneumoperitoneum
Abnormal calcifications: Gallstones supine and erect
Air-fluid levels
CT correlate: Gallstones
Abnormal Calcifications: Nephrolithiasis
CT correlate: Nephrolithiasis
Abnormal calcifications: Appendocolith
http://www.hawaii.edu/medicine/pediatrics/pemxray/v6c18.html
Plain film imaging of the Abdomen: Bones
http://www.szote.u-szeged.hu/radio/trauma2/a2trau3a.htm
Radiology at UNC
The Department of Radiology at the University of North Carolina at Chapel Hill has eight clinical sections: Abdominal Imaging (Body CT, US, MRI, Flouro studies
such as UGI and SBFT, Biopsies) Breast Imaging Cardiopulmonary Imaging (Chest, Cardiac) Musculoskeletal Imaging (Bone, ER RR, MSK MRI’s) Neuroradiology (brain/spine CT & MRI; lumbar punctures) Nuclear Medicine (wide variety, PET-CT, bone scans,
Cards) Pediatric Imaging (wide variety) Vascular-Interventional (wide variety)
Calling Radiology Try to call the right reading room (RR).
Each subspecialty has their own reading room Calling the Neuro reading room to talk about a
chest x ray will not get you far (like asking ENT to perform an appendectomy)
When paging, it’s nice to put your name/pager number immediately after the call back number
After hours: 6-8850 Lower Level/ER RR 216-2826 Upper Level (VIR, Doppler US, MRI)
DON’T call 6-8850 during the day unless it’s an MSK radiology issue
When you call, identify yourself, and expect whoever answers to identify themselves. Improves accountability Always good policy to know who talked to
Please page us if our report is confusing!
Parting thoughts (for Radiology and beyond!)
Always try to be polite. This will be difficult when you are sleep deprived and overworked, but “please” and “thank you” go a long way in maintaining cordial relationships with your co-workers.
Try to resist the urge to “bad mouth” other specialties.
Speak up when you see something wrong!
RECAP
o CT is a great tool but provides a high does of radiationo Provide good indications!
o IV Contrast + Sick Kidneys = BAD
o If worried about free air in the abdomen, order upright or decubitus films
o Radiology is a cool specialty. Think whether it’s a good fit as you go through the year.
Thanks for listening! Questions?
Hx: Please Evaluate New Line.“?!@#!%!”