MR imaging of distal ileal and colorectal chronic inflammatory bowel disease--diagnostic accuracy of 1.5 T and 3 T MRI compared to colonoscopy.

purposeThe aim of this study was to investigate the diagnostic accuracy of MR enterography (MRE) for detection of distal ileal and colorectal inflammatory bowel disease (IBD) and to evaluate whether 3 T MRI can provide a higher diagnostic performance compared to 1.5 T.

methodsA retrospective review of patients with known or suspected IBD who underwent MRE and colonoscopy within 3 months was performed. For analysis, the bowel was divided into six segments. Compared with colonoscopy, the accuracy values for MRI diagnosis of overall and each magnetic field strength were calculated, and the differences between 1.5 T and 3.0 T were compared. The image quality was scored separately for both field strengths and compared.

resultsEighty-eight patients were included in the study. On a patient basis, MRE had an overall sensitivity of 92.1 % and specificity of 72.0 %. On a segment basis, the sensitivity and specificity were 79.1 % and 93.6 %, respectively. Concerning severely inflamed segments, per-segment sensitivity increased from 79.1 to 94.7 %. The comparison of accuracy values between the two field strengths showed no statistically significant difference. B1 homogeneity and overall artifacts were not significantly different between 3.0 T and 1.5 T imaging. Compared to colonoscopy, MRI found four more fistulas confirmed at subsequent surgery.

conclusionsMRI has a high diagnostic accuracy for detection of distal ileal and colorectal IBD. 3 T MRI can be considered equivalent but not superior compared to 1.5 T imaging in this context. In addition, our findings suggest MRE to be a valuable tool in detecting surgically relevant pathologies (fistulas) with higher accuracy than colonoscopy.