Role of 3.0-T MR colonography in the evaluation of inflammatory bowel disease.

Conventional colonoscopy combined with histologic analysis represents the standard of reference for the evaluation of colorectal disease and is usually the initial examination in patients with a suspected or established diagnosis of inflammatory bowel disease (IBD). However, it is increasingly being recognized that colonoscopy is limited to providing information regarding mucosal alterations. Colonoscopy cannot help estimate the depth of involvement of colonic lesions and does not provide information regarding the presence of extraluminal complications such as abscesses or fistulas. Recent technologic advances in magnetic resonance (MR) imaging, with its high spatial and tissue resolution, have raised expectations as to the potential role of this modality in the evaluation of colonic lesions in patients with IBD, as either a complement or an alternative to colonoscopy. MR colonography allows the characterization of colonic changes in acute and chronic IBD and can depict a wide spectrum of related lesions, including ulcers, edema, wall thickening, hyperemia, and fistulas, as well as potential extraluminal complications. The bulk of available evidence indicates that MR colonography can be useful as a problem-solving tool in the evaluation of IBD, as an alternative to colonoscopy whenever tissue sampling is not required, and for the assessment of the entire colon in cases of incomplete colonoscopy.