8) Abdomen

Question 1

KUB

Answer 1

• Kidneys, ureters, bladder

- Order this exam when you need a flat film of the abdomen only (e.g. kidney stones)

Question 2

Abdominal series

Answer 2

• Upright abdomen
• Flat abdomen
• Left lateral decubitis

Question 3

Upright abdomen

Answer 3

• Pt must be upright for at least 5 min

- Necessary when evaluating the abdomen for free air or bowel obstruction

Question 4

Flat abdomen

Answer 4

• AKA supine abdomen, KUB (kidneys, ureters, bladder)

Question 5

Left lateral decubitus

Answer 5

• To be done if patient is unable to stand for upright abdomen

Question 6

Systematic study of the abdominal plain film

Answer 6

• Spine, ribs, pelvis
• Upper quadrants, flanks, and abdominal organs for masses or calcifications
• Flanks of the lower abdomen

Question 7

Abdominal plain films evaluate

Answer 7

• Bowel gas pattern
• Intra-abdominal calcifications
• Flank stripe (properitoneal fat line)

Question 8

Bowel gas pattern key concepts

Answer 8

• Valvulae conniventes
• Haustral lines
• Large bowel is located more peripherally
• Air fluid level is normally seen in the stomach in the upright abdomen

Question 9

Valvulae conniventes

Answer 9

• Small bowel

- Parallel lines that extend across the bowel diameter

Question 10

Haustral lines

Answer 10

• Large bowel

- Lines do not extend across the diameter of the bowel

Question 11

Intra-abdominal calcifications key concepts

Answer 11

• Calcified gallstones
• Calcified mesenteric nodes
• Appendicolith
• Phlebolith
• Pancreatic calcifications
• Urinary tract stones (anywhere from the kidneys, through the ureters to the bladder)
• Tumors, classically calcifications of benign uterine fibroids

Question 12

Phlebolith

Answer 12

• Calcified venous thrombi with central lucencies

Question 13

Appendicitis key concepts

Answer 13

• Most patients with acute appendicitis have normal abdominal plain films
• Occasionally, a calcified appendicolith can be identified in the right lower quadrant
• A localized ileus in the right lower quadrant or obliteration of the right flank stripe are other radiographic signs

Question 14

Abdominal/pelvic abscess key concepts

Answer 14

• May see obliteration of the flank stripe

- CT is the imaging method of choice

Question 15

Two types of bowel obstructions

Answer 15

• Non-mechanical (ileus)

- Mechanical

Question 16

Non-mechanical (ileus) bowel obstruction

Answer 16

• AKA paralytic ileus

- Occurs because peristalsis stops

Question 17

Mechanical bowel obstruction

Answer 17

• Occurs when the bowel is physically blocked and its contents can not pass the point of obstruction

Question 18

Bowel obstruction key concepts

Answer 18

• Partial or complete, can occur anywhere in the small bowel
• Small bowel diameter greater than 3cm or large bowel diameter greater than 5cm is considered abnormal
• Small bowel obstructions present with air-fluid levels on upright or decubitus films seen in association with dilated small bowel loops

Question 19

Ileus key concepts

Answer 19

• An intestinal ileus appears radiographically as an enlargement of the GI tract
• The stomach, small and large bowel, all dilate

Question 20

Differential diagnosis of ileus includes

Answer 20

• Trauma
• Medications
• Peritonitis
• Electrolyte disturbances

Question 21

A localized ileus or sentinel loop

Answer 21

• Seen as a focal dilated loop of small bowel seen adjacent to an area of inflammation.
• Seen in patients with cholecystitis, pancreatitis, or appendicitis

Question 22

Mechanical bowel obstruction differential in adults

Answer 22

• Adhesions
• Hernias
• Neoplasms

Question 23

Mechanical bowel obstruction differential in pediatrics

Answer 23

• Intussusception
• Hernia
• Appendicitis

Question 24

Bowel obstruction, volvulus, intussuception

Answer 24

• Small bowel obstruction = adhesions
• Volvulus = twisting
• Intussuception = telescoping

Question 25

Volvulus key concepts

Answer 25

• A closed loop obstruction of the bowel; can lead to ischemia and necrosis
• Most common in the sigmoid colon and cecum
• Diagnosis is made by Barium enema or endoscopy

Question 26

Cecal and sigmoid volvulus Hx

Answer 26

• Usually seen in elderly debilitated patients with chronic obstruction
• Caused by a “twisting” of the bowel

Question 27

Cecal volvulus abdominal x-ray findings

Answer 27

• Displaced cecum (normal location is within the right iliac fossa)
• Small and large bowel obstruction up to the point of torsion
• Paucity of gas in the distal colon

Question 28

Sigmoid volvulus abdominal x-ray findings

Answer 28

• Twisted dilated loop seen in abdominal film

- Forms a central double wall that converges in the lower quadrant (known as the “coffee bean” sign)

Question 29

Intussuception key concepts

Answer 29

• Most patients are children less than 2 years old
• Telescoping of the bowel
• Usually idiopathic, but can be seen following upper respiratory tract infections
• Seen on plain film radiographs as a small bowel obstruction

Question 30

Diagnosis and treatment of pediatric intussuception

Answer 30

• Made by single contrast barium enema

Question 31

Flank stripe key concepts

Answer 31

• Should appear as a longitudinal fat lucency located along the lateral aspects of the abdominal wall
• Intra-abdominal fluid may obliterate the flank stripe

Question 32

Free peritoneal fluid

Answer 32

• Large amounts of free air in the abdomen will appear more radiolucent (darker) than normal
• Large amounts of free fluid in the abdomen will appear more radiopaque (whiter) than normal

Question 33

Free intraperitoneal air

Answer 33

• Accumulates under the right hemidiaphragm on an upright film
• Free air under the left hemidiaphragm is less common because of the phrenicolic ligament

Question 34

For the patient who cannot stand, a _____ will demonstrate air above the liver

Answer 34

• Left lateral decubitus

Question 35

Probably the most common cause of free air

Answer 35

• Perforated viscus

Question 36

Pneumoperitoneum-differential diagnosis

Answer 36

• Perforated viscus
  1. Peptic ulcer
  2. Diverticulitis
  3. Appendicitis
  4. Toxic megacolon
  5. Intestinal infarct
• Neoplasm
• Iatrogenic (recent surgery including laparoscopy)