Levels of Faecal Calprotectin and Magnetic Resonance Enterocolonography Correlate with Severity of Small Bowel Crohn's Disease: A Retrospective Cohort Study.

Few studies have evaluated the usefulness of fecal calprotectin (FC) or magnetic resonance enterography (MRE) in diagnosing active Crohn's disease (CD) of the small bowel. In the study, we investigated the reliability of FC and MRE in assessing the activity of ileal CD and further explored the relationship between levels of FC and MRE scores. A total of 221 patients were diagnosed with ileal or ileo-colitis CD in our department between July 2012 and October 2016. The global magnetic resonance index of activity (MaRIA) correlated with the simple endoscopic score for CD (SES-CD) (r = 0.527, P = 0.005). When analysed segment-by-segment, a significant correlation was still observed (r = 0.590, P < 0.001). The SES-CD correlated closest with FC (r = 0.503), followed by CRP (r = 0.461), ESR (0.377) and the CDAI (r = 0.320). In receiver operating characteristic (ROC) analyses, the FC cut-off value of mucosal healing was 213.1 μg/g, with 76.1% sensitivity and 66.7% specificity. As for MaRIA, a cut-off value of 6.8 for each segment provided a sensitivity of 100% and a specificity of 79.2%. No agreement between MaRIA and FC levels was found. In conclusion, a combination of FC levels and MaRIA could be effective in monitoring mucosal activity in patients with small bowel CD.