Magnetic resonance enterography is feasible and reliable in multicenter clinical trials in patients with Crohn's disease, and may help select subjects with active inflammation.

Background Reliable tools for patient selection are critical for clinical drug trials. Aim To evaluate a consensus-based, standardised magnetic resonance enterography (MRE) protocol for selecting patients for inclusion in Crohn's disease (CD) multicenter clinical trials. Methods This study recruited 20 patients [Crohn's Disease Activity Index (CDAI) scores: <150 (n = 8); 150-220 (n = 4); 220-450 (n = 8)], to undergo ileocolonoscopy and two MREs (with and without colonic contrast) within a 14-day period. Procedures were scored centrally using, Magnetic Resonance Index of Activity (MaRIA), and both Crohn's Disease Endoscopic Index of Severity (CDEIS) and Simplified Endoscopic Score (SES-CD). Results 37 MREs were acquired. Both MREs were evaluable in 16 patients for calculation of test-retest and inter-reader reliability scores. The MaRIA scores for the terminal ileum had excellent test-retest and inter-reader reliability, with correlations >0.9. The proximal ileum showed strong within-reader agreement (0.90-0.96), and fair between-reader agreement (0.59-0.72). MRE procedures were tolerable. MaRIA scores correlated with CDEIS and SES-CD (0.63 and 0.71), but not with CDAI (0.34). MRE identified 3 patients with intra-abdominal complications, who would otherwise have been included in clinical trials. Furthermore, both MRE and ileocolonoscopy identified active bowel wall inflammation in 2 patients with CDAI <150, and none in 1 patient with CDAI >220. Data quality was good/excellent in 85% of scans, and fair or better in 96%. Conclusions Magnetic resonance enterography of high-quality and reproducibility was feasible in a global multi-centre setting, with evidence for improved selectivity over CDAI and ileocolonoscopy in identifying appropriate CD patients for inclusion in therapeutic intervention trials.