P146. Magnetic resonance imaging evaluation of inflammatory activity in Crohn's disease. A Moroccan monocentric experience
1Military Hospital mohammed V, Gastroenterology, Rabat, Morocco
Background: MRI enterography in the evaluation of the gastrointestinal tract is preferred because of lack of ionizing radiation, high tissue contrast, reasonably safe profile of gadolinium-based contrast media, ability to perform real-time and functional imaging. While several published papers affirm the diagnostic usefulness of MRI enterography in CD, most of the recent research has been targeted at the assessment of the degree of inflammatory activity in the affected loops, with the main purpose of monitoring the therapy and detecting the onset of complications. Aim of Study: To assess the diagnostic accuracy of magnetic resonance imaging (MRI) in prospectively differentiating between fibrotic and active inflammatory small bowel stenosis in patients with Crohn's disease (CD).
Methods: Prospective study was performed from January 2010 to October 2011 in our center; 55 patients with Crohn's disease proven histologically underwent coronal and axial MRI scans after oral administration of polyethylene glycol solution. All MRI examinations were performed in the supine position with a 1.5 T magnet. A stenosis was judged present if a small bowel segment had >80% lumen reduction as compared to an adjacent normal loop and mural thickening of >3 mm. Seventeen patients were excluded from this study because CD involved mainly their large bowel. The final study group included 32 patients (20 females and 12 males; age range 1668 years, with a mean value of 36 years) with proven CD, in whom a good-quality MRI enterography examination demonstrated the presence of a small bowel stenosis.
Results: A small bowel stenosis was identified in 32 out of 55 patients. Fibrosis was confirmed at histology in all of the 13 patients, who underwent surgery within one week of the MRI examination. In the remaining 19 patients, an active inflammatory stenosis was suspected and remission of the obstructive symptoms was obtained by means of medical treatment. MRI had 96% sensitivity, 100% specificity, and 98% accuracy in the diagnosis of fibrotic stenosis.
Conclusions: In patients with CD, MRI with oral administration of the biphasic contrast agent allows for a reliable differentiation between fibrotic and active inflammatory small bowel stenosis, based on the combined evaluation of the degree of wall enhancement and the T2 signal intensity.