MRI of the Colon (Colonography): Results

Key Points

Magnetic resonance imaging (MRI) has been increasingly studied as a diagnostic tool for the evaluation of the colon. Without the use of intralu-minal colonic distension methods or following colonic distension with the use of either positive or negative luminal contrast medium (MR colonogra-phy), cross-sectional images can be acquired of the entire abdomen. Subsequent evaluation of the complete colonic wall can be executed using multipla-nar reformations of the source data set with optional three dimensional (3D) rendering, in the case of a MR colonography data set. Although most investigators primarily focused on the ability of detecting colorectal polyps and masses using MR colonogra-phy, a wide spectrum of colorectal disorders can be evaluated by utilizing MRI to examine the colon.

Until now, no consensus has been reached regarding the technique and optimal bowel preparation of MR colonography. Current evidence suggests that MR colonography has sufficient accuracy for detecting colorectal cancer and clinical significant polyps. Efforts are made to replace rectal enemas by gaseous distension as in CT colonography, which may improve acceptance of MR colonogra-phy. The wide ranges of fecal tagging schemes give the possibility of limited bowel preparation in MR colonography. In addition, MR has a potential role in determining disease activity in inflammatory bowel disease of the colon and in incomplete colonoscopy.