Accuracy of intestinal ultrasonography in the evaluation of patients with moderate-to-severe ulcerative colitis starting infliximab therapy

Abstract

Background Intestinal ultrasound (IUS) is accurate in detecting active ulcerative colitis (UC), but its role in repeated monitoring during biologic therapy remains to be established. This study aimed to assess correlations between IUS findings and the Mayo endoscopic score (MES), clinical and biochemical indices, and to evaluate the utility of IUS for monitoring infliximab (IFX) therapy and predicting outcomes.

Methods In this prospective open-label study, patients with moderate-to-severe UC starting IFX were assessed at baseline and at week 14. Flexible sigmoidoscopy, IUS and measurement of fecal calprotectin levels were performed at both time points. Correlations between bowel wall thickness (BWT) and MES, C-reactive protein (CRP), calprotectin, and the Simple Clinical Colitis Activity Index (SCCAI) were analyzed across both visits.

Results Thirty-two patients completed baseline evaluations and 21 completed follow up. Median age was 38 years; 53% were male. Disease extent was left-sided in 41% and extensive in 59%. BWT showed moderate correlations with MES (r=0.43, P=0.0015), and CRP (r=0.40, P=0.007), and a weak correlation with calprotectin (r=0.19, P=0.25). No significant differences in BWT, MES, CRP or calprotectin were observed at either time point. The only significant improvement was in SCCAI, from 7 (4.8-8) to 3 (1-5) (P=0.009). Baseline BWT and MES did not differ significantly
between responders and non-responders.

Conclusions BWT measured by IUS correlates with endoscopic and biochemical markers of disease activity. IUS may serve as a reliable, noninvasive alternative to endoscopy for monitoring treatment response in UC.

Keywords Intestinal ultrasound, ulcerative colitis, infliximab, Mayo endoscopic score, bowel wall thickness

Ann Gastroenterol 2025; 38 (6): 641-647