Magnetic resonance enterography in Crohn's disease: a comparison with the findings at surgery

Magnetic resonance (MR) enterography is a radiation-free small bowel investigation which identifies luminal and extra-luminal pathology in patients with Crohn's disease. Most studies have validated MR against conventional radiology. We evaluated the results of MR enterography by comparison with findings at elective surgery for patients with Crohn's disease, including complex pathology.

Between January 2007 and March 2012 the results of preoperative MR enterography for Crohn's disease in consecutive patients in one unit were compared with the detailed findings at surgery.

Fifty-one patients underwent 55 laparotomies during the study period. MR enterography identified the presence of Crohn's disease in the distal ileum in 33/34 patients, in the proximal ileum in 7/12 patients, in the jejunum in 7/8 patients, in the large bowel in 10/11 patients and in the duodenum in one of two patients. MR enterography identified ileo-enteric fistula in 10/12 patients, ileosigmoid fistula in all of seven patients and other fistulae in 10/11 patients. An abscess was identified on MR enterography in eight of nine patients. Within abnormal distal ileal segments, the mean contrast enhancement ratio of acute inflammation was 2.39 ± 0.59 compared with 1.82 ± 0.63 (P < 0.05) in segments with fibrosis only.

Magnetic resonance enterography identifies small bowel Crohn's disease with an accuracy similar to or better than those of previously published series. Fistulation, abscess formation and large bowel disease can be reliably identified and disease activity assessed. Normal, uninvolved small bowel length can also be measured. Discrete proximal small bowel lesions may not always be detected. In our practice, MR enterography has replaced conventional radiology in the assessment of symptomatic patients with Crohn's disease.