A simple MR enterography assessment of Crohn disease activity based on the most affected bowel segment: A retrospective cohort study.

This retrospective study aimed to propose and validate a simple magnetic resonance enterography (MRE)-based assessment of Crohn disease (CD) activity based on the most inflamed bowel segment. A total of 252 adult patients who underwent MRE for suspected or known CD were included. Three abdominal radiologists assessed the simplified Magnetic Resonance Index of Activity (sMARIA) score using MRE. The Maximal Segmental Score was defined as the largest segmental sMARIA among 6 evaluated bowel segments in a patient. The global sMARIA was obtained from the sum of each segmental sMARIA score. Correlation analysis was performed between global sMARIA and Maximal Segmental Score. For patients with endoscopic results, correlation analysis was performed between the simple endoscopic score for CD (SES-CD) and maximal segmental score. The diagnostic performance of the maximal segmental score to predict endoscopic remission (SES-CD <3) was evaluated using the receiver operating characteristic curve analysis. Global sMARIA and Maximal Segmental Score correlated strongly (ρ = 0.954, 95% confidence interval: 0.941-0.964). In 77 patients with endoscopic results, global sMARIA (ρ = 0.685) and Maximal Segmental Scores (ρ = 0.634) moderately correlated with SES-CD without significant difference between 2 scores (P = .17). The area under the receiver operating characteristic curve to predict endoscopic remission was 0.850 for global sMARIA and 0.843 for Maximal Segmental Score without significant difference between them (P = .73). The Maximal Segmental Score based on the evaluation of the most inflamed bowel segment can be a simple practical MRE-based index to represent overall disease activity and predict endoscopic remission in CD.