Avoiding contrast-enhanced sequences does not compromise the precision of the simplified MaRIA for the assessment of non-penetrating Crohn's disease activity

Objectives Patients with Crohn's disease (CD) require multiple assessments with magnetic resonance enterography (MRE) from a young age. Standard MRE protocols for CD include contrast-enhanced sequences. Gadolinium deposits in brain tissue suggest avoiding gadolinium could benefit patients with CD. This study aimed to compare the accuracy of the simplified Magnetic Resonance Index of Activity (sMaRIA) calculated with and without contrast-enhanced sequences in determining the response to biologic drugs in patients with CD. Methods This post hoc analysis of a prospective study included patients with CD with endoscopic ulceration in >= 1 intestinal segment starting biologic drug therapy. Two blinded radiologists used the sMaRIA to score images obtained at baseline and week 46 of treatment first using only unenhanced sequences (T2-sMaRIA) and 1 month later using both unenhanced and enhanced images (CE-sMaRIA). We calculated the rates of agreement between T2-sMaRIA, CE-sMaRIA, and ileocolonoscopy for different conceptualizations of therapeutic response. Results A total of 46 patients (median age, 36 years [IQR: 28-47]) were included. Agreement with ileocolonoscopy was similar for CE-sMaRIA and T2-sMaRIA in identifying ulcer healing (kappa = 0.74 [0.55-0.93] and 0.70 [0.5-0.9], respectively), treatment response (kappa = 0.53 [0.28-0.79] and 0.44 [0.17 - 0.71]), and remission (kappa = 0.48 [0.22-0.73] and 0.43 [0.17-0.69]). The standardized effect size was moderate for both CE-sMaRIA = 0.63 [0.41-0.85] p < 0.001 and T2-sMaRIA = 0.58 [0.36-0.80] p < 0.001. Conclusions sMaRIA with and without contrast-enhanced images accurately classified the response according to different therapeutic endpoints determined by ileocolonoscopy.

Automated summary

Simplified Magnetic Resonance Index of Activity (sMaRIA) calculated with or without contrast-enhanced sequences accurately classified the response to biologic drugs in patients with Crohn's disease.