MRI of the small bowel in patients with Crohn's disease.

PURPOSE OF REVIEW: To highlight the advances in MRI of the small intestine in patients with Crohn's disease. MRI of the gut has become more feasible with improved spatial resolution and speed of the MR sequences allowing parallel evaluation for both disease activity and extra-enteric complications.

RECENT FINDINGS: Recent literature highlights excellent diagnostic accuracy of MR enterography (MRE) that is comparable to computed tomography enterography (CTE). Compared to CTE the image quality is not quite as good, and there is slightly more interobserver variability in interpretation. Despite these performance characteristics, the overall diagnostic yield of MRE is comparable to CTE. The lack of radiation exposure related to MRE is a significant strength, especially in Crohn's population that by virtue of their younger age, body habitus and potential need for repeated imaging, is at highest risk of potential cancer from radiation exposure due to diagnostic imaging. MRE should not be viewed as a 'safer' version of a CTE. The physics of MRI allows the application of unique sequences that add novel insights not possible with other imaging modalities.

SUMMARY: MRE is a highly effective technique for assessing Crohn's disease. We are only starting to explore new MRI sequences and the future of this technology is extremely exciting.