Objective: The objectives of our study were to establish the efficacy of a 5-point MR enterocolonography classification for assessing Crohn disease (CD) activity, compare this classification with a validated MRI score (i.e., the MR index of activity [MaRIA]), and compare both with endoscopic findings, which were assessed using the Crohn disease endoscopic index of severity (CDEIS).
Materials and methods: Seventy (derivation cohort) and 50 (validation cohort) patients with CD were retrospectively enrolled in this study. We developed a 5-point MR enterocolonography classification that consists of visual assessments alone. MR enterocolonography results were evaluated for each bowel segment (rectum; sigmoid, descending, transverse, and ascending colon; terminal and proximal ileum; and jejunum) by one observer in the derivation phase and independently by three observers in the validation phase using the 5-point MR enterocolonography classification lexicon and MaRIA. Areas under the ROC curves (AUCs) in discriminating endoscopic deep ulcers were compared between the MR enterocolonography classification and MaRIA. Interobserver reproducibility was assessed using weighted kappa coefficients.
Results: The AUCs of the MR enterocolonography classification were 89.0% in the derivation phase and 88.5%, 81.0%, and 77.3% for the three observers in the validation phase. The AUCs of the MR enterocolonography classification were statistically noninferior to those of MaRIA (p < 0.001). The cross-validation accuracy was 81.9% in the derivation phase and 81.5% in the validation phase. The MR enterocolonography classification showed good reproducibility.
Conclusion: The 5-point MR enterocolonography classification was shown to be effective for evaluating CD activity in the large and small bowel.
Keywords: Crohn disease; MRI; comparative study; scoring methods.