Radiology-1/12/16

Question 1

_____ densities outline the margins of the organs in radiographs.

Blood and pus appear as ___ densities on radiographs

Answer 1

Fat/water

Water

Question 2

A rule of thumb is that free air goes to the ____ of the abdominal cavity and is typically best seen on an upright radiograph

Answer 2

Most superior portion

Question 3

This patient position is beneficial for detecting air between the liver and right lower ribs and may need to be used in patients who are too sick to be placed in an upright position

Answer 3

Left side down decubitus with a cross table lateral film

Question 4

Where can air under the diaphragm be best seen?

Answer 4

Best seen on the right side because the liver offers a distinct outline between the free air and the soft tissues

Difficult to see on the left side-difficult to distinguish from air in the stomach or splenic flexure

Question 5

____ is produced when both sides of the bowel wall become outline by air. Normally, only the inner aspect of the bowel may be defined by air.

Answer 5

Rigler’s sign-

When free air exists, both sides of the bowel wall can be seen (double-wall sign). Typically seen on supine radiographs. Requires a significant amount of free air within the abdomen

Question 6

Air can collect in Morrison’s pouch which is____

Answer 6

Inferior to the liver and above the right kidney

Question 7

Causes of free air-Perforated viscus=

Answer 7

Peptic ulcer disease
Penetrating trauma
Diverticulitis
Bowel obstruction

Question 8

Causes of free air-Inflammatory conditions=

Answer 8

Toxic megacolon
TB
Peritoneal inflammation

Question 9

Causes of free air-Iatrogenic=

Answer 9

Postsurgical/post laparoscopy/endoscopy

Peritoneal dialysis

Question 10

What are you looking for when evaluating SOFT TISSUE MASSES?

Answer 10

Evaluate for bowel displacement-Lack of gas in an area that normally contains air
Extrinsic impression of a mass on a bowel loop
Edge of a soft tissue mass

Question 11

Where is it normal to see air in the abdomen?

Answer 11

Air in the stomach is always normal

Normal to see air scattered in 1-2 loops of small bowel which is of normal caliber (abormal is > 3 cm)

Almost always see air in the rectum and sigmoid

Question 12

Describe normal air-fluid levels for:
A) Stomach
B) small bowel
C) large bowel

Answer 12

A) Stomach (unless on a supine film)
B) Small bowel (2-3 levels allowed)
C) Large bowell (NOT typically seen)

Question 13

Compare SMALL BOWEL versus LARGE BOWEL

Answer 13

Small–> tends to be more centrally located; valvulae extend across entire lumen; Tends to be peripherally located; haustra do NOT extend from wall to wall

Question 14

____ is a bowel dilatation without mechanical obstruction caused by metabolic disorders, meds, ischemia, recent surgery, localized abdominal pain caused by appendicitis/pancreatitis, etc, neuromuscular and motility abnormalities, sprue

Answer 14

Ileus-Abnormal gas pattern

Question 15

____ is characterized by 1-2 persistently dilated loops of small or large bowel, air in rectum or segmoid, may see air fluid levels but are nondifferential (equal heights within same bowel loop), and may resemble early or partial SBO

Answer 15

Ileus

Question 16

____ is characterized by dilated small bowel loops, little gas in colon (particularly absent in the rectum), and the key is that there is disproportionate air in the small bowel

Answer 16

Mechanical SBO

Question 17

____ is characterized by air being seen to the point of obstruction. There is little to no air in the rectum and/or sigmoid colon, little to no gas in the small bowel unless the ileocecal valve is incompetent

Answer 17

Mechanical LBO

Question 18

What are some causes of SBO?

Answer 18

Adhesions
Hernias
Cancer-intrinsic and extrinsic
Volvulus

Question 19

____ is often used to evaluate specific complaints localized to the esophagus. It is used in the work-up of gastric diseases including peptic ulcer disease; in the work up of small bowel pathology (Crohn’s); in the work up of colon pathology (diverticular disease or polyps); can be used to evaluate the ureters and urinary bladder (trauma causes or vesicoureteral reflex)

Answer 19

Fluoroscopy

Question 20

____ is a screening tool in the work up of patients with abdominal pain, especially used to evaluate for cholelithiasis. There is no radiation

Answer 20

Ultrasound

Question 21

____ is used frequently in the acute setting but also in the workup of nonspecific abdominal pain. There is radiation.

Answer 21

CT

Question 22

____ is often used to evaluate a specific issue seen on prior imaging studies. I.e., an indeterminate liver mass or renal mass. There is no radiation

Answer 22

MRI

Question 23

How does AIR appear in a radiographic density?

Answer 23

Dark

Question 24

How does METAL appear in a radiographic density?

Answer 24

White (light)

Question 25

How do FAT and SOFT TISSUE appear in radiographic densities?

Answer 25

Fat-Not as dark as air but darker than soft tissue

Soft tissue-Darker than bone and metal but lighter than fat and air

Question 26

What are the main modalities used in radiology for imaging of the abdomen?

Answer 26

Radiographs
Fluoroscopy
Ultrasound
CT
MRI