How are Crohn’s disease and ulcerative colitis distinguished on cross-sectional imaging?
Comparison of Cross sectional Imaging Features of Crohns Disease and Ulcerative Colitis
|CROHN’S DISEASE||ULCERATIVE COLITIS|
|Distribution||May involve any part of the gastrointestinal tract; most commonly affects small bowel, followed by colon, and less commonly esophagus, stomach, or duodenum||Involves colon starting at the rectum and moving proximally|
|Pattern of spread||Skip lesions||Continuous|
|Mean wall thickness||12 mm||8 mm|
|Wall morphology||Eccentric, segmental, sometimes with pseudosacculations||Diffuse, symmetric|
|Enhancement pattern||“Target” sign in active disease, “fat halo” sign in chronic disease||“Target” sign in active disease, “fat halo” sign in chronic disease|
|Terminal ileal involvement||95%||25% backwash ileitis in setting of pancolitis|
|Distribution of fibrofatty change||Mesenteric distribution||Perirectal distribution; associated with widening of the presacral space|
|Complications||Fistulas, sinus tracts, and abscess formation (due to transmural extent of disease), stricture formation, colorectal cancer, lymphoma||Toxic megacolon, stricture formation, sclerosing cholangitis, colorectal cancer (higher risk than in Crohn’s disease), lymphoma|
What percent of patients with Crohn’s disease present with isolated colonic involvement?