Magnetic resonance colonography for the evaluation of colonic inflammatory bowel disease: correlation with conventional colonoscopy.

OBJECTIVE

To identify and evaluate quantitative parameters of colonic inflammation in patients with inflammatory bowel disease (IBD) compared with conventional colonoscopy (CC).

METHODS

Retrospectively, 37 consecutive patients who underwent MR colonography (MRC) from March 03- April 06 were included in this study. Patients with suspected and known IBD (n = 22) constituted the study group (SG) and those evaluated for colonic polyps (n = 15) constituted the control group. All patients in the SG underwent CC. Magnetic resonance colonography was performed using a gadolinium-enhanced coronal 3-dimensional gradient-echo sequence. The colon was divided into segments, and each segment was evaluated in consensus by 2 abdominal radiologists blinded to the CC findings. Readers assessed the bowel wall thickness index, the signal intensity index of colonic wall, and the caliber of vasa recta in all segments. Indices calculated from colonoscopically diseased and nondiseased segments were compared using Mann-Whitney U test. Receiver operator characteristic analysis was used to determine the use of these indices in predicting the presence of colonic inflammation.

RESULTS

There were 60 colonoscopically diseased and 33 nondiseased segments in the SG. For all 3 MR indices, there was a significant difference (P < 0.05) in these indices between diseased and nondiseased segments. Bowel wall thickness index, signal intensity index, and vasa recta values of 0.074, 118% and 0.25 mm, respectively, had 63% sensitivity and 80% specificity for predicting colonic inflammation.

CONCLUSIONS

Inflammatory changes in the colon can be demonstrated on MRC in patients with IBD with moderate sensitivity and high specificity using quantitative parameters.