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.“?!@#!%!”