MR enterography in IBD patients

Purpose: The traditional imaging of Crohn's disease has relied on barium studies, sonography and CT examinations. With modern technology MRI become able to asses the small intestine as well. We wanted to evaluate the role of modern MRI techniques in the diagnostic workup of IBD patients.

Materials and methods: In a 3-years period 327 patients (135 female, mean age 24.7 years) were referred to our unit with suspected or known IBD located to the small intestne. In our protocol the patient preparation consisted o fan owernight fasting with slight bowel preparation and orally administered conrast agent using forced gastric emptying and smooth muscle relaxants without nasojejunal tube insertion. Fast, high resolution breath-hold sequences were used coupled with movie like functional images of the intestinal motility and imaging of the perianal involvement. In 163 patients the clinical activity was available at the time of MR enterography. In 8 patients the results of subsequent surgery were reached.

Results: Good bowel distension was achieved using our protocol in 265/327 cases. The MRI activity signs correlated in 76.6% of the cases with the clinical activity. Fibrous strictures determined by functional MR images were confirmed in 7 of 8 operated cases. Perianal fistulous tracts were categorized according to Parks classification, abscesses were confirmed or excluded, and activity of perianal disease could be graded.

Conclusion: MR enterography can provide all the information needed for small intestinal IBD patients in one single exam. It detects wall thickening, mesenteric proliferation, lymph node involvement, abscesses and fistulas also in the perianal region and is able to differentiate active disease from remission and fibrous strictures from inflammatory ones. It has no radiation burden thus can be repeated in the often young IBD patients (compared to the radiation dose of CT enteroclysis equivalent to approximately 6 years background radiation).