Increased Rectal Wall Thickness May Predict Relapse in Ulcerative Colitis: A Pilot Follow-Up Study by Ultrasonographic Colonoscopy

Background and Study Aims: Ulcerative colitis is a chronic inflammatory bowel disease with repeated remission and relapse, although the occurrence of relapse is difficult to predict. We performed a prospective study to determine whether there is a relationship in ulcerative colitis between the inflammatory changes identified by endoscopic ultrasonography (EUS) and relapse. Patients and Methods: Participants were 23 ulcerative colitis patients who had not suffered a relapse for 1 month, with a Seo activity index ≤ 150 and Baron grade 1 at colonoscopy. The thickness of the first to the third layer of the rectal wall in these patients was measured by EUS at the start of the study. They were subsequently followed up for 1 year to record any relapses, defined as having a Seo activity index >150 and Baron grade ≥2 at colonoscopy. Results: Relapse occurred in eight patients. The mean activity index of the relapsed patients was 187.3 (95% confidence interval (Cl), 166.4-208.2) at the end of the study. The thickness of the first to the third layer of the rectal wall, as evaluated by EUS at the beginning of the study, was significantly larger in the relapse group (mean 2.73 mm, 95% CI 2.13-3.33 mm) than in the nonrelapse group (1.79 mm; 1.56-1.99 mm; P = 0.0001). Conclusions: Catheter probe-assisted endoluminal ultrasonography may predict the occurrence of relapse of ulcerative colitis.