GI Imaging

Question 1

What options are there for imaging the GI system?

Answer 1

Abdominal X-ray,
Barium swallow, enema and follow through,
Water soluble contrast studies,
CT,
MRI,
Angiography.

Question 2

When might abdominal X-ray be used?

Answer 2

When CT is unavailable.

Volvulus of large bowel and toxic megacolon show up well on AXR. Can be used to see if stones have passed.

Question 3

Where are valvulae conniventes found?

How do they differ from haustra?

Answer 3

Found in the small intestine,
Thin,
Cross the entire wall.

Question 4

What is the 3,6,9 rule?

Answer 4

Small bowel distended after 3cm, large bowel after 6cm and caecum after 9cm.

Question 5

What does the coffee bean sign indicate on AXR?

Answer 5

(Sigmoid) volvulus. Colon twists around its mesentery and distends.

Question 6

What features of toxic megacolon may be seen on X-ray?

Answer 6

Colonic dilatation,
Oedema,
Pseudopolyps,
Mucosal islands.

Question 7

What does an erect CXR look for in the abdomen?

What are common causes of this?

Answer 7

Pneumoperitoneum.
Peptic ulcers,
Tumours,
Obstruction,
Trauma including recent surgery.

Question 8

What method has largely replaced the use of a barium swallow?

Answer 8

Upper GI endoscopy.

Question 9

What are the advantages and disadvantages of ultrasound?

Answer 9

Quick, cheap and portable. Good for visualising soft tissue. Poorly visualises other structures and is very user dependant.

Question 10

What landmarks are found at the T12 spinal level?

Answer 10

Aortic hiatus of the diaphragm and the coeliac trunk.

Question 11

What landmarks are found at L1? (Transpyloric plane)

Answer 11

Pelorus of stomach,
Fundus of gallbladder,
Neck of pancreas,
Superior mesenteric artery origin,
Hilum of kidneys (left).

Question 12

What is found at the L3 spinal level?

Answer 12

Umbilicus,

Inferior mesenteric artery.

Question 13

What is found at L4 spinal level?

Answer 13

Iliac crest and bifurcation of the abdominal aorta into the common iliac vessels.