The role of magnetic resonance enterography in the evaluation of activity of paediatric Crohn's disease

Purpose: The objective of this study is to evaluate the feasibility of our protocol of bowel preparation to MRE investigation in paediatric population diagnosed with Crohn's disease in terms of sensitivity of MRE compared to colonoscopy; moreover, to validate a correlation between Magnetic Resonance Index of Activity (MaRIA) and the Simple Endoscopic Score for Crohn's Disease (SES-CD) and the Paediatric Crohn's Disease Activity Index (PCDAI). Methods and Materials: We retrospectively reviewed MRE investigations on 32 patients (age 7-18; median 14.5) diagnosed with CD. Activity disease was measured by PCDAI. MRE were performed at 1.5 T after bowel cleansing andbowel luminal distension with PEG solution (20 ml/Kg) as oral contrast andgadolinium chelate (0.1 mmol/Kg) as intravenous contrast. MRE was evaluatedwith MaRIA score taking into account the small bowel and colon findings. 24 out of 32 patients' ileo-colonoscopies were reviewed and scored with SES-CD; Spearman's Rho correlation was used. Results: The sensitivity of MRE related, respectively, to terminal ileum and colonic involvement was 71% and 94% on a per-patient basis and 51% per segment basis. Small bowel involvement, except terminal ileum, was detected in 13 patients. A significant correlation was observed between global MaRIA score and SES-CD (n=24; r=0.70; p < 0.05); moderate correlation between global MaRIA score and PCDAI (n=32; r=0.50; p < 0.01). Conclusion: The performed MRE protocol allowed to detect both ileum and colonic involvement in paediatric population with CD and supported the global MaRIA score as an imaging-based quantitative index of activity disease correlated with endoscopic and clinical activity indices.