Colonic Crohn's disease: value of magnetic resonance colonography for detection and quantification of disease activity.

Conventional colonoscopy combined by histological examination, represents the standard for the evaluation of colorectal pathologies and usually is the first examination for the evaluation of patients with suspected or established diagnosis of Crohn's disease (CD). However, information provided by colonoscopy is limited to mucosal alterations since the technique is unable to evaluate transmural changes or presence of extraluminal complications such as abscesses or fistula. Technological advances in magnetic resonance (MR) raised expectations on the potential role of this imaging modality for evaluation of the gastrointestinal tract based on the high spatial and tissue resolution as well as lack of ionizing radiation. Available evidence indicates that MR colonography (MRC) can be a useful tool as an alternative or complementary to endoscopy for the detection of activity and assessment of severity in colonic CD. In this article, we review the technical aspects of MRC and the spectrum of findings that provide valuable information for the evaluation of colonic CD. Potential applications and limitations of MRC are also discussed.