Correlation of the endoscopic and magnetic resonance scoring systems in the deep small intestine in Crohn's disease

Background: There are no widely accepted endoscopic or magnetic resonance scoring systems to evaluate deep small intestinal lesions in Crohn's disease (CD). This study aimed to determine whether the simplified endoscopic activity score for Crohn's disease (SES-CD) and the Magnetic Resonance Index of Activity (MaRIA) could be adapted for assessing CD lesions in the deep small intestine. Methods: Magnetic resonance enterocolonography and single-balloon enteroscopy were prospectively performed in 125 patients with CD. SES-CD and MaRIA were applied to the deep small intestine. The correlation between the SES-CD and MaRIA was evaluated. Results: Endoscopic and magnetic resonance active lesions were detected in the terminal and proximal ileal segments at a similar rate. The total MaRIA scores correlated well with the total SES-CD scores (R = 0.808, P < 0.001). A MaRIA score of ≥11 had a high sensitivity, specificity, and diagnostic accuracy for ulcerative lesions that were defined by enteroscopy (sensitivity: 78.3%; specificity: 98.0%). Similarly, an MaRIA score of ≥7 had a high sensitivity, specificity, and diagnostic accuracy for all mucosal lesions defined by enteroscopy (sensitivity: 87.0%; specificity: 86.0%). Conclusions: The MaRIA closely correlates with the SES-CD in the deep small intestine, indicating these scoring systems can be used to assess deep small intestinal lesions. We also showed the validity of MaRIA to evaluate the active lesions in the deep small intestine.