Assessment of inflammation activity in the small and large bowel using the MaRIAs index for Crohn’s disease

Aim: to evaluate diagnostic value of magnetic resonance enterocolonography (MR-enterocolonography) with the use of the segmental index MaRIAs (Simplified Magnetic Resonance Index of Activity) for inflammation activity in small and large intestine colon compared with ileocolonoscopy.Patients and Methods: the prospective cohort study included 58 patients with Crohn’s disease aged 19–45 years. All patients underwent MR-enterocolonography with intravenous contrast and ileocolonoscopy. MR-enterocolonography assessed inflammatory activity in the large and small intestine (406 segments) using the MaRIAs index (segmental). MRI data were compared with ileocolonoscopy.Results: ileocolonoscopy showed no signs of inflammatory activity in 71 (71/406, 17.5%) segments. In 168 (168/406, 41.3%) segments endoscopic signs of low or moderate inflammatory activity were detected, in 167 (167/406, 41.2%) segments inflammatory activity with the presence of ulcers were detected. MR-enterocolonography did not detect any activity in 121 (121/406, 29.8%) segments (0 points by MaRIAs index), in 285 (285/406, 70.2%) segments, the inflammation activity was revealed by MaRIAs index from 1 to 5 points. There was a moderate agreement (Cohen’s Kappa: 0.57) between the data of MR-enterocolonography and ileocolonoscopy in detection of affected segments. ROC analysis revealed that with the value of the MaRIAs index (segmental) of 1 point or more with sensitivity of 82.0% and specificity of 92.0% (AUC 0.85), it is possible to consider the presence of inflammatory activity of any severity, and with index value of 2 points or more with sensitivity of 75.0% and specificity of 91.0% (AUC 0.91) can diagnose the severe inflammation with ulcers.Conclusion: the results obtained revealed the value of MaRIAs index and the further study to evaluate the effectiveness of conservative treatment of Crohn’s disease is needed.