Accuracy of magnetic resonance enterography in the preoperative assessment of patients with small bowel Crohn's disease

Aim to assess the accuracy of magnetic resonance-enterography in predicting the extension, location and characteristics of the small bowel segments affected by Crohn's disease. Method This is a prospective study including a consecutive series of 38 patients with small bowel Crohn's disease who underwent surgery at a specialized colorectal unit of a tertiary hospital. Preoperative magnetic resonance enterography was performed in all patients, following a homogeneous protocol, within the three months prior to surgery. A thorough exploration of the small bowel was performed during the surgical procedure, using calibration spheres, according to the discretion of the surgeon. The accuracy of magnetic resonance enterography in detecting affected areas in the small bowel by Crohn′s disease was assessed. Magnetic resonance enterography findings were compared to surgical and pathological findings. Results Thirty-eight patients with 81 lesions were included in the study. During surgery, twelve lesions (14.8%) that were not described on magnetic resonance enterography, were found. Seven of them were detected exclusively by using calibration spheres, passing unnoticed at surgical exploration. Magnetic resonance enterography had 90% accuracy in detecting the location of the stenosis (75.0% sensitivity, 95.7% specificity). Magnetic resonance enterography did not precisely diagnose the presence of an inflammatory phlegmon (accuracy 46.2%), whereas it was more accurate in detecting abscesses or fistulas (accuracy 89.9% and 98.6%, respectively). Conclusions Magnetic resonance enterography is a usefull tool in the preoperative assessment of patients with Crohn's disease. However, a thorough intra-operative exploration of the entire small bowel is still necessary. This article is protected by copyright. All rights reserved.