Multiple Rectal Ulcers (39 of 110)

CT is valuable for the detection and characterization of
ulcerative colitis. CT typically demonstrates
circumferential, symmetrical wall thickening with fold
enlargement. Thickening of the colon wall (mean, 7.8 mm;
standard deviation, 1.9) may be present, with
inhomogeneous attenuation, a target appearance of the
rectum, and the proliferation of perirectal fat. The normal
colonic wall has a maximal thickness of 3 mm with the
lumen distended and 5 mm with the lumen collapsed. In
comparison, Crohn colitis causes greater bowel wall
thickening (mean, 11 mm; standard deviation, 5.1) Such
thickening appears in association with homogeneous
attenuation, fistula and abscess formation, and mesenteric
abnormalities.