GI Imaging

Question 1

Endoscopy

Answer 1

Usually requires sedation
Laxative for lower GI
Risk of perforation
Can be poorly tolerated
Allows therapeutic procedures - ERCP, stenting

Question 2

Fluoroscopy

Answer 2

Radiation
Requires contrast (e.g. barium)
Requires distension of tube with gas or air
Good for looking at perforation, leak, blockage

Question 3

Ultrasound

Answer 3

Uses sonar technology
Fast, cheap, safe
First line
Requires pt to be healthy weight 
Gas reflects ultrasound back - so not that useful in looking at GI tract
Useful for gallstones

Question 4

CT

Answer 4

Good resolution
Not good for tissue differentiation
Uses radiation
Main diagnostic tool: diagnose disease, stage malignancy, assess repsonse to treatment

Question 5

PET-CT (Positron Emission Tomography - CT)

Answer 5

Functional imaging of radioactive tracer uptake
fused with anatomical information from CT
FDG (fluorodeoxyglucose) used as tracer, accumulates in metabolically active cells

Question 6

MRI

Answer 6

No radiation
Good for soft tissue differentiation
Slow
For non-invasive imaging of biliary tree and small bowel, staging of rectal cancer, diagnosing liver lesions
Can't be used in pts with pacemakers