Anatomic Radiology

Question 1

What can ‘appear’ as water density on radiographs

Answer 1

blood, pus and obviously..water

Question 2

Pneumoperitoneum can be best seen on what radiograph position?

Answer 2

upright - free air rises to the most superior portion of the abdominal cavity

Question 3

What position can detect air between the liver and right lower ribs in a radiograph?

Answer 3

left side down decubitus with a cross table lateral film - used for sick patients who cant stand

Question 4

Where is air under the diaphragm best seen?

Answer 4

right side bc the liver offers a distinct outline between the free air and soft tissues

Question 5

Why can the left side under the diaphragm be difficult to see if there is free air?

Answer 5

because of gastric bubbles in the stomach or splenic flexure

Question 6

What color is air on a radiograph?

Answer 6

black

Question 7

What is Rigler’s sign?

Answer 7

both sides of the bowel wall becomes outlined by air (double-wall sign)
Seen in supine radiographs
Lots of free air in abdomen

Question 8

What part of the bowel is defined by air in normal conditions in the radiograph?

Answer 8

inner aspect

Question 9

Free air can collect over the ___ on supine radiographs and outline edges of the ______ ______

Answer 9

liver

falciform ligament

Question 10

What is Morrison’s pouch?

Answer 10

Place that free air can collect that is inferior to the liver and above the right kidney

Question 11

What are the main causes of free air?

Answer 11

peforated viscus (peptic ulcer, penetrating trauma)
Inflammatory conditions (Toxic megacolon)
Iatrogenic (postsurgical)
Intrathoracic causes
Pneumatosis intestinalis

Question 12

What can cause a lack of gas in an area that normally contains air in a radiograph?

Answer 12

Soft tissue mass that displaces bowel

Question 13

You can see ________ on renal stones, gallstones, appendicolith, vas deferens, gallbladder walls, pancreas, etc

Answer 13

Calcifications/ossifications

Question 14

Air in the _____ is always normal

Answer 14

stomach

Question 15

What is the normal caliber of air in small bowel?

Answer 15

1-2 loops of air

abnormal is greater than 3 cm

Question 16

Where do you ALMOST always see air in a normal radiograph

Answer 16

rectum and sigmoid

Question 17

Describe normal air-fluid levels in the stomach, small bowel, and large bowel

Answer 17

stomach always seen unless supine

small: two or three levels allowed
large: not typically seen

Question 18

Describe the small bowel in a radiograph

Answer 18

tends to be more centrally located
valvulae extend across the entire lumen
less than 3 cm in diameter

Question 19

Describe the large bowel in a radiograph

Answer 19

tends to be peripherally located

haustra do not extend from wall to wall

Question 20

What is illeus?

Answer 20

bowel dilation without mechanical obstruction due to metabolic disorders, medications, ischemia, localized abdominal pain due to appendicitis, pancreatitis etc

1-2 persistently dilated loops of small or large bowel
air in rectum or sigmoid
may see air fluid levels, but are nondifferential
may resemble early or partial SBO

Question 21

What is mechanical SBO?

Answer 21

dilated small bowel loops
little gas in colon
absent in rectum
disproportionate air in small bowel

Question 22

What is mechanical LBO?

Answer 22

air seen to point of obstruction
little to no air in rectum and/or sigmoid colon
little to no gas in small bowel, unless ileocecal valve is incompetent (large bowel may then decompress into small and cause apparent SBO)

Question 23

What are the causes of SBO?

Answer 23

adhesions
hernias
cancer - intrinsic and extrinsic
volvulus

Question 24

What is fluroscopy used for?

Answer 24

'live xray'
incomplete colonoscopy 
post surgical changes 
esophagus 
diverticulosis, apple core lesion, scleroderma

Question 25

What is ultrasound used for?

Answer 25

abdominal pain, especially to evaluate for cholelithiasis (gallstones)
hepatic steatosis and renal cell carcinoma
there is no radiation
Best option

however, not good for pancreas

Question 26

What is CT used for?

Answer 26

Acute setting but also in workup of nonspecific abdominal pain
downside - radiation

contrast used if kidneys are okay
NO contrast if renal stones
easy to see renal stones w/o contrast anyways

Question 27

What is MRI used for?

Answer 27

often used to evaluate specific issue seen on prior imaging studies
like a liver mass or renal mass
there is no radiation