Small Bowel Motility Quantified by Cine MRI to Predict Longer-Term Response in Patients with Crohn's Disease Commencing Biological Therapy: The Motility Study.

Background: Small bowel Crohn's disease (SBCD) is increasingly treated with biological therapies. Predicting response or remission (RoR) for individual patients is difficult and complicates treatment strategy. We aimed to determine if motility magnetic resonance imaging (mMRI) is superior to CRP and fecal calprotectin (FC) for the prediction of RoR at 1 year in patients commencing biologics for SBCD.

Methods: Prospective, multicenter (n = 13) cohort study of patients with active non-stricturing SBCD requiring anti-TNFα or anti-IL-12/23 treatment. We measured mMRI and CRP at baseline and post-induction (visit 2: 12-30 weeks), and FC in a subset. RoR was assessed at 1 year using clinical and structural magnetic resonance enterography parameters. We compared sensitivity, specificity, and area under the receiver operating characteristic curve (ROC-AUC) of changes in mMRI and CRP to predict RoR at 1 year. Secondary outcomes compared mMRI with FC, and prediction of improved quality of life (QoL).

Results: Eighty-six participants completed all assessments. Stable or improved mMRI at visit 2 was more sensitive than normalization of CRP for RoR (mMRI:71.0%, 95%CI 52.0-85.8; CRP:45.2%, 95%CI 27.3-64.0%, P = .008) but less specific (mMRI:30.9%, 95%CI 19.1-44.8; CRP:67.3%, 95%CI 53.3-79.3%, P < .001). There was no significant difference in ROC-AUC (mMRI:0.48; CRP:0.53, P = .65). Similar results were obtained for FC. None of mMRI, CRP, or FC predicted patient QoL at 1 year.

Conclusions: Although improved mMRI is more sensitive than CRP and FC to predict RoR at 1 year, it is less specific. No factor predicted patient QoL. Motility MRI remains a marker of disease activity at given timepoints.