Objective Transabdominal ultrasonography (TUS) is a non-invasive procedure that is reportedly useful for managing ulcerative colitis (UC) and assessing bowel wall thickness (BWT), the most common measure of mucosal inflammation. However, the exact range of BWT that reflects disease activity remains undetermined. The present study clarified the BWT due to disease activity by comparing the use of TUS in each segment of the colon versus using colonoscopy (CS) and determined the usefulness of TUS in patients with UC. Methods We divided the colon into five segments and measured the BWT using TUS. The results were then compared to the Mayo endoscopic subscore (MES) classification to determine the accuracy of BWT measurement. Patients Eighty patients with UC who underwent TUS within 14 days of CS were retrospectively registered. Results We evaluated a total of 268 images depicting each segment among 80 patients with UC. The BWT was positively correlated with endoscopic activity (0.69, p<0.0001). In each segment, the relationship between a BWT>2 mm and an MES>0 had the highest sensitivity, specificity, and accuracy (0.85-1.00, 0.67-0.92, and 0.81-0.97, respectively). Conclusion This study concluded that TUS was a useful method of detecting an MES>0, which indicates the presence of inflammation and its location among UC patients. MES>0 was found to be highly accurate when a BWT>2 mm was considered positive. This non-invasive method may help control disease activity in patients with UC.
Keywords: Mayo endoscopic subscore classification; bowel wall thickness; transabdominal ultrasonography; ulcerative colitis.