302 Imaging of the GI tract Flashcards
How do you know it’s a small bowel obstruction on an abdominal x-ray?
Everything will be centrally placed
And there will be valvulae connivences, lines that go all across the bowel. In the large bowel they won’t go all the way across
What is a gallstone ileus?
A rare form of bowel obstruction where a gallstone blocks the bowel
Caused by repeated gallstones that end up causing a fistula
What is Rigler’s triad?
The 3 radiological signs to diagnose gallstone ileus
- Small bowel obstruction
- Pneumobilia
- Ectopic gallstone
What is Pneumobilia?
Air within the biliary tree of the liver
Suggests an abnormal communication between the biliary tract and the intestines, or infection by gas-forming bacteria
Why is there small bowel dilatation in large bowel obstruction?
Caused by increased pressure and inflammation caused by the obstruction
If there no dilatation, it puts the patient at greater risk of rupture
What is sigmoid volvulus?
When a portion of the intestine twists around its blood supply
Coffee bean appearance is present
What is Rigler’s sign?
Shows perforation
The bowel will appear very clear because there is gas inside and outside of the bowel, giving it very clear boundaries
What is mural oedema a sign of?
Inflammation or ischaemia of the bowel
The bowel wall and haustrations are very large and thick
Eg. toxic megacolon
What are haustrations?
The things that give the large bowel a segmented appearance
What are contrast studies used to diagnose?
Barium swallow: for functional problems, after OGD, cancer, benign tumours
Water soluble studies: post anastomosis
What is achalasia?
There is a failure of relaxation of the lower oesophageal sphincter causing dysphagia and distention of the oesophagus
Why is ultrasound not often used to view the bowel?
Because it’s full of gas that makes it hard to see anything
What is endoscopic ultrasound?
An endoscope probe with an ultrasound attached
Used for staging of cancers
What is a pneumoperitoneum?
Gas in the peritoneal cavity
What is MR enterography used for?
Oedema
Motility (can take videos)
Fibrosis
Inflammation
Anatomy and disease activity
