8) Abdomen Flashcards
KUB
- Kidneys, ureters, bladder
- Order this exam when you need a flat film of the abdomen only (e.g. kidney stones)
Abdominal series
- Upright abdomen
- Flat abdomen
- Left lateral decubitis
Upright abdomen
- Pt must be upright for at least 5 min
- Necessary when evaluating the abdomen for free air or bowel obstruction
Flat abdomen
- AKA supine abdomen, KUB (kidneys, ureters, bladder)
Left lateral decubitus
- To be done if patient is unable to stand for upright abdomen
Systematic study of the abdominal plain film
- Spine, ribs, pelvis
- Upper quadrants, flanks, and abdominal organs for masses or calcifications
- Flanks of the lower abdomen
Abdominal plain films evaluate
- Bowel gas pattern
- Intra-abdominal calcifications
- Flank stripe (properitoneal fat line)
Bowel gas pattern key concepts
- Valvulae conniventes
- Haustral lines
- Large bowel is located more peripherally
- Air fluid level is normally seen in the stomach in the upright abdomen
Valvulae conniventes
- Small bowel
- Parallel lines that extend across the bowel diameter
Haustral lines
- Large bowel
- Lines do not extend across the diameter of the bowel
Intra-abdominal calcifications key concepts
- 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
Phlebolith
- Calcified venous thrombi with central lucencies
Appendicitis key concepts
- 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
Abdominal/pelvic abscess key concepts
- May see obliteration of the flank stripe
- CT is the imaging method of choice
Two types of bowel obstructions
- Non-mechanical (ileus)
- Mechanical
Non-mechanical (ileus) bowel obstruction
- AKA paralytic ileus
- Occurs because peristalsis stops
Mechanical bowel obstruction
- Occurs when the bowel is physically blocked and its contents can not pass the point of obstruction
Bowel obstruction key concepts
- 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
Ileus key concepts
- An intestinal ileus appears radiographically as an enlargement of the GI tract
- The stomach, small and large bowel, all dilate
Differential diagnosis of ileus includes
- Trauma
- Medications
- Peritonitis
- Electrolyte disturbances
A localized ileus or sentinel loop
- Seen as a focal dilated loop of small bowel seen adjacent to an area of inflammation.
- Seen in patients with cholecystitis, pancreatitis, or appendicitis
Mechanical bowel obstruction differential in adults
- Adhesions
- Hernias
- Neoplasms
Mechanical bowel obstruction differential in pediatrics
- Intussusception
- Hernia
- Appendicitis
Bowel obstruction, volvulus, intussuception
- Small bowel obstruction = adhesions
- Volvulus = twisting
- Intussuception = telescoping
Volvulus key concepts
- 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
Cecal and sigmoid volvulus Hx
- Usually seen in elderly debilitated patients with chronic obstruction
- Caused by a “twisting” of the bowel
Cecal volvulus abdominal x-ray findings
- 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
Sigmoid volvulus abdominal x-ray findings
- Twisted dilated loop seen in abdominal film
- Forms a central double wall that converges in the lower quadrant (known as the “coffee bean” sign)
Intussuception key concepts
- 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
Diagnosis and treatment of pediatric intussuception
- Made by single contrast barium enema
Flank stripe key concepts
- Should appear as a longitudinal fat lucency located along the lateral aspects of the abdominal wall
- Intra-abdominal fluid may obliterate the flank stripe
Free peritoneal fluid
- 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
Free intraperitoneal air
- Accumulates under the right hemidiaphragm on an upright film
- Free air under the left hemidiaphragm is less common because of the phrenicolic ligament
For the patient who cannot stand, a _____ will demonstrate air above the liver
- Left lateral decubitus
Probably the most common cause of free air
- Perforated viscus
Pneumoperitoneum-differential diagnosis
- Perforated viscus
1. Peptic ulcer
2. Diverticulitis
3. Appendicitis
4. Toxic megacolon
5. Intestinal infarct - Neoplasm
- Iatrogenic (recent surgery including laparoscopy)
