IUS to assess UC treatment response

IUS to assess UC treatment response

January 24, 2023

Issue 02

Clinical Question

Can intestinal ultrasound assess treatment response in UC?

Editor’s Bottom Line

Intestinal ultrasound can assess the activity of ulcerative colitis accurately and with high inter-observer agreement.


de Voogd F, van Wassenaer EA, Mookhoek A, et al. Intestinal Ultrasound Is Accurate to Determine Endoscopic Response and Remission in Patients With Moderate to Severe Ulcerative Colitis: A Longitudinal Prospective Cohort Study. Gastroenterol. 2022;136(6):1569–81; https://www.gastrojournal.org/article/fulltext


In this multicenter European study, investigators prospectively enrolled 27 consecutive patients with moderate-to-severe ulcerative colitis (UC) who were set to undergo treatment with tofacitinib. Participants underwent clinical, biochemical, endoscopic, histologic and intestinal ultrasound (IUS) assessments at baseline and eight weeks after treatment outset. Blinded investigators interpreted IUS findings, which were then correlated with endoscopic, histologic and clinical outcomes.

Endoscopic remission and improvement were defined as endoscopic Mayo scores (EMS) of 0 or 1, respectively, while endoscopic response was defined as a reduction of one or more points on the EMS from baseline to follow-up. The IUS parameter of interest was bowel wall thickness (BWT), as it has been previously identified as a predictor of endoscopic improvement.

Findings showed that BWT was significantly correlated with EMS scores at both baseline and follow-up in the sigmoid and descending colon, and was significantly correlated with UC Endoscopic Index of Severity (UCEIS) scores and Robarts Histopathologic Index (RHI) scores at both baseline and eight-week follow-up.

Specifically, there were significant differences in median BWT in the sigmoid colon for those in endoscopic remission (1.4 mm vs. 4.0 mm for remission vs. no remission; p=0.016) and those with endoscopic improvement (1.8 vs. 4.5 mm, p<0.0001), while those with endoscopic response saw a median 58.1% decrease in BWT from baseline to eight weeks, compared to a 13.4% reduction in BWT among those without an endoscopic response (p=0.018). There were significant differences in BWT in the mucosa, submucosa and the muscularis propria among those with or without treatment response.

Analyses identified moderate correlation between BWT and histological scores and good correlation between BWT and clinical activity scores at eight weeks.

A BWT cut-off value of 2.8 mm predicted endoscopic remission in all patients (area under the curve [AUC] = 0.87) while a BWT of 3.9 mm predicted endoscopic improvement in all patients (AUC = 0.92).

There was near-perfect interobserver agreement in interpreting BWT on IUS in both the sigmoid and descending colon.


Study Design: Prospective longitudinal

Funding: None

Allocation: Consecutive

Setting: Multicenter

Level of Evidence: 1b