Comparison of an Endoscopic Scoring System and the Simplified Magnetic Resonance Index of Activity in Patients with Small Bowel Crohn?s Disease

Background/Aims: The newly derived simplified magnetic resonance index of activity (MARIAs) has not been verified in comparison to balloon-assisted enteroscopy (BAE) for patients with small bowel Crohn's disease (CD). We studied the correlation of MARIAs with simple endoscopic scores for CD (SES-CD) of the ileum based on magnetic resonance enterography (MRE) and BAE in patients with small bowel CD.Methods: Fifty patients with small bowel CD who underwent BAE and MRE concurrently within 3 months from September 2020 to June 2021 were enrolled in the study. The primary outcome was the correlation between the active score of ileal SES-CD (ileal SES-CDa)/ileal SES-CD and MARIAs based on BAE and MRE. The cutoff value for MARIAs identifying endoscopically active/ severe disease, defined as ileal SES-CDa/ileal SES-CD of 5/7 or more, was analyzed.Results: Ileal SES-CDa/ileal SES-CD and MARIAs showed strong associations (R=0.76, p<0.001; R=0.78, p<0.001). The area under the receiver operating characteristic curve of MA-RIAs for ileal SES-CDa >_5 and ileal SES-CD >_7 was 0.92 (95% confidence interval, 0.88 to 0.97) and 0.92 (95% confidence interval, 0.87 to 0.97). The cutoff value of MARIAs for detecting active/ severe disease was 3. A MARIAs index value of >_3 identified ileal SES-CDa >_5 with a sensitiv-ity of 85% and specificity of 87% and detected ileal SES-CD >_7 with a sensitivity of 87% and specificity of 86%.Conclusions: This study validated the applicability of MARIAs compared to BAE-based ileal SES-CDa/SES-CD. (Gut Liver, Published online April 4, 2023)