In Crohn’s disease, ileocolonoscopy (IC) identifies mucosal inflammation and magnetic resonance enterography (MRE) detects transmural inflammation (CD). For a study, researchers sought to determine the link between the simplified magnetic resonance index of activity (MARIAs) and IC-measured inflammation in children with newly diagnosed CD. Retrospective analysis of 140 CD patients aged 6–18 years who had baseline IC and MRE within five weeks of diagnosis. Marias were determined for each intestinal segment (terminal ileum [TI], ascending colon, transverse colon, descending colon, sigmoid colon, and rectum), defined as (1 × thickness > 3 mm) + (1x edema) + (1x fat stranding) + (2 x ulcers). To compare Marias to IC results, sensitivity and specificity were calculated using receiver operating characteristic (ROC) curves.

The cutoff Marias ≥1 identified TI segments with active inflammation with 84% sensitivity, 73% specificity, 85% positive predictive value (PPV), 70% negative predictive value (NPV), and area under the curve (AUC) 0.782 (95% CI 0.689–0.876) using IC as the reference standard. With 87% sensitivity, 76% specificity, 87% PPV, 76% NPV, and an AUC of 0.814 (95% CI 0.712–0.916), the cutoff Marias ≥2 detected TI segments with severe lesions. Sensitivity was low across the board for all colonic segments. In children with newly diagnosed CD, the Marias were practical and accurate in measuring disease activity in the TI but not in the colon. Although Marias can be used to track TI illness activity over time, a comprehensive evaluation still requires both IC and MRE.