Magnetic Resonance Imaging-based ileal motility quantification predicts stricture response to biologic therapy in Crohn's disease.

Objective Strictures are a common feature of Crohn’s disease (CD), impairing bowel function, complicating treatment, and often leading to surgery. Predicting which lesions are responsive to medical therapy and which will become obstructive represents an important clinical goal. We aim to characterize ileal strictures in patients with CD by exploring the bowel wall motility in patients receiving biologic agents and evaluate motility’s potential role in predicting therapeutic response compared with standard, transmural MRI biomarkers. Materials and Methods This retrospective study included subjects aged 10–28 with stricturing CD who underwent initiation or escalation of biologic therapy and clinically indicated MRE within a two-month window. Clinical response and disease activity were evaluated up to six months after therapy initiation or adjustment. Subjects were categorized as "non-responders" if they experienced worsening disease activity, required discontinuation of therapy, or needed surgical intervention. Simplified MR indexes of activity (sMaRIA) assessed the terminal ileum, and motility data were processed using GIQuant software. Sociodemographic and clinical variables were compared between responders and non-responders. Results A total of 40 subjects (52.5% female; mean age 19.77 ± 5.13) were included, with 15 (37.5%) classified as non-responders. No significant differences were observed in age, gender, stricture length, wall thickness, stricture volume, or T2-weighted signal intensity. However, mean motility (176.03 ± 128.63 vs. 67.83 ± 33.88; p = 0.006) and its standard deviation (72.06 ± 55.55 vs. 30.27 ± 25.79; p = 0.017) were significantly higher in responders. Motility outperformed sMaRIA (AUC 0.812 vs. 0.613; p = 0.07) in predicting response. Conclusion Quantitative MRI motility assessment was superior to traditional MRI biomarkers in predicting response to biologic therapy in adolescents and young adults with stricturing CD.