Week 10 - imaging of the GI tract Flashcards
From which view should an AXR be taken?
-A->P
What is the structure for interpreting an AXC?
- Air/gas
- Bowel
- Calcification and bones
When would the bowel not be visible?
-If it was entirely full of fluid
What are valvulae conniventes?
-Lines across the entire wall of the small intestine
How is the small intestine differentiated from the large on AXR?
- large -> haustra do not go all the way across
- small -> valvulae conniventes go all the way across
An obstruction is likely present when a small bowel loop is bigger than what size?
-3cm
An obstruction is likely present when a large bowel loop is bigger than what size?
-9cm
How does sigmoid volvulus often look on an AXR?
-Coffee bean sign in left iliac fossa
What causes toxic megacolon? How does it present on AXR?
- Infection
- Chronically dilated with pseudopolyps
Lead pipe colon is a sign of what?
-UC
What is thumb printing?
-Odematous thickened haustra
What soft tissues should be identified on an AXR except bowels?
-Liver, spleen, stomach, kidneys
When would you do an erect CXR?
-Pneumoperitoneum
Name 4 possible causes of pneumoperitoneum
- Peptic ulcer
- Diverticular
- Tumour
- Obstruction
What is the major disadvantage to CT?
-Very high dose of radiation
What does CT require?
-IV contrast and knowledge of anatomical levels
MRIs have no radiation and give the best spatial resolution. Why is it then that they are not always used?
- Time consuming
- Anything which moved proves problematic eg small bowel, unwell patient
What is the major disadvatage to abdominal USS?
-Highly user dependant
What are the advatages to abdominal USS?
- Cheap
- Fast
- Portable
What is indicative of chronic prancreatitis on AXR?
-Retroperitoneal calcificaton
Describe a barium swallow
- Oesophagus visualised as barium is swallowed in upright and prone positions
- Allow visualisation of motility abnormalities and anatomical lesions
When is a barium meal used?
-To visualise stomach and duodenum
When is a barium follow through used?
-To visualise small bowel
When is the best time to use USS?
-Fluid filled lesions
