No Bowel Cleansing Needed With Investigative Screening Technique

NEW YORK AUG 14, 2007 (Reuters Health) - Magnetic resonance (MR) colonography, which uses fecal tagging to avoid the need for bowel cleansing, is accurate in detecting adenomatous lesions at risk for becoming cancer, new research indicates.

However, further refinements to improve the image quality of tagging are needed as many colonic segments could not be evaluated. Moreover, improvements are needed to better detect lesions <5 mm in diameters, according to the report in the August issue of Gut.

The findings stem from a study of 315 adults older than 50 years who underwent screening. A tagging agent solution (5% Gastrografin, 1% barium and 0.2% locust bean gum) was ingested 2 days before MR colonography.

No bowel cleansing agents were given, although rectal water enema was administered during imaging for bowel distension. No sedative or analgesic medications were given.

The findings on MR colonography were compared with those obtained with conventional colonoscopy, the report indicates.

Dr. Christiane A. Kuehle, from University Hospital Essen in Germany, and colleagues found that 4% of colonic segments had poor image quality due to the presence of untagged fecal material.

Overall, MR colonography was 83.0% sensitive in detecting adenomatous polyps >5 mm. By contrast, just 16 of 153 lesions <5 mm were detected with this modality as were just 9 of 127 hyperplastic polyps. The overall specificity of MR colonography was 90.2%.

"Because of the high diagnostic accuracy and the possibility of simultaneous polypectomy, conventional colonoscopy will keep on playing a leading role as a screening tool," the authors conclude. "However, for patients unwilling to undergo colonoscopy, MR colonography should be regarded as an attractive alternative."

SOURCE:

• Gut 2007;56:1079-1085.