ischemic colitis

precipitating factors: volvulus, carcinoma, cardiovascular disease, history of aortoiliac reconstruction (2%) with ligation of IMA
abrupt onset of lower abdominal pain and rectal bleeding
location: splenic flexure (80%) + rectosigmoid ("watershed areas")
BE:
- single contrast prefered (lesions may become effaced with double contrast)
- serrated mucosa; pseudopolyposis; transverse ridging; "thumbprinting" on mesenteric side; deep ulcers
CT:
- thickening of wall; irregular lumen ("thumbrinting")
- curvilinear collection of intramural gas
- portal and mesenteric venous air
- blood clot in SMA / SMV
Angio (similar to inflammatory disease):
- normal / slightly attenuated arterial supply
- mild acceleration of arteriovenous transit time