Simplified Magnetic Resonance Index of Activity Is Useful for Terminal Ileal but not Colonic Disease in Pediatric Crohn Disease

Abstract

Background: Ileocolonoscopy (IC) detects mucosal inflammation and magnetic resonance enterography (MRE) detects transmural inflammation in Crohn disease (CD). We aimed to evaluate the relationship between the simplified magnetic resonance index of activity (MARIAs) and measures of inflammation by IC in children with newly diagnosed CD. Methods: Retrospective review of 140 patients 6-18 years of age with CD who had baseline IC and MRE within 5 weeks of diagnosis. MARIAs was calculated for each intestinal segment (terminal ileum [TI], ascending colon, transverse colon, descending colon, sigmoid colon, rectum), defined asSensitivity and specificity were derived using receiver operating characteristic (ROC) curves to compare MARIAs to IC findings. Results: Using IC as the reference standard, 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% confidence interval [CI] 0.689-0.876). The cutoff MARIAs !2 identified TI segments with severe lesions with 87% sensitivity, 76% specificity, 87% PPV, 76% NPV, and AUC 0.814 (95% CI 0.712-0.916). There was poor sensitivity for all colonic segments. Conclusion: The MARIAs is feasible and accurate in reflecting disease activity in the TI, but not in the colon, in children with newly diagnosed CD. Although the MARIAs may be useful for monitoring TI disease activity over time, full assessment continues to require both IC and MRE.

Intestinal ultrasound as a non-invasive tool to monitor inflammatory bowel disease activity and guide clinical decision making

“…Interobserver agreement for IUS was higher than MRE in the small bowel for new diagnosis [82% ( k = 0.64)] and for relapsed patients [81% ( k = 0.63)] and in the colon for new diagnosis [64% ( k = 0.27)] and relapsed patients [78% ( k = 0.56)][ 52 ]. Furthermore, a retrospective study in children with IBD demonstrated that MRE is not accurate for the assessment of colonic disease, with the simplified Magnetic Resonance Index of Activity unable to identify severe lesions in colonic segments[ 53 ].…”

Intestinal Ultrasound for the Pediatric Gastroenterologist: A Guide for Inflammatory Bowel Disease Monitoring in Children: Expert Consensus on Behalf of the International Bowel Ultrasound Group (IBUS) Pediatric Committee

“…Both IUS and MRE have a high sensitivity for detecting small bowel Crohn disease (CD) activity with substantial practitioner agreement for the presence of active ileal inflammation. This suggests that both modalities are valid tools for disease activity assessment, supporting the use of IUS as an accurate tool for serial monitoring during routine exam visits (6–9). Presently, there is a lack of standardized approach to bedside IUS among gastroenterologists.…”

The Pediatric Inflammatory Crohn’s Magnetic Resonance Enterography Index: A Step Forward for Transmural Pediatric Crohn’s Disease Monitoring and Healing

“…The Magnetic Resonance Index of Activity (MaRIA) and simplified MaRIA (sMaRIA) index have become excellent tools for monitoring transmural inflammation in adults with CD, but are limited by the need for rectal contrast and real-world accuracy in children with CD. [4][5][6] In turn, the development of the Pediatric Inflammatory Crohn's Magnetic Resonance Enterography Index (PICMI) has the potential to be transformative, filling a critical need for pediatric patients with CD, becoming the first validated cross-sectional imaging scoring system in children to discriminate transmural disease activity at a single time point. PICMI has the ability to measure treatment responsiveness and healing, that is both accurate and without the need for rectal contrast.…”