Magnetic resonance (MR) colonography in the detection of colorectal lesions: a systematic review of prospective studies.

OBJECTIVE: To determine the diagnostic accuracy of MR-colonography for the detection of colorectal lesions.

METHODS: A comprehensive literature search was performed for comparative MR-colonography studies, published between May 1997 and February 2009, using the MEDLINE, EMBASE and Cochrane databases. We included studies if MR-colonography findings were prospectively compared with conventional colonoscopy in (a)symptomatic patients. Two reviewers independently extracted study design characteristics and data for summarising sensitivity and specificity. Heterogeneity in findings between studies was tested using I (2) test statistics. Sensitivity and specificity estimates with 95% confidence intervals (CI) were calculated on per patient basis and summary sensitivity on per polyp basis, using bivariate and univariate statistical models.

RESULTS: Thirty-seven studies were found to be potentially relevant and 13 fulfilled the inclusion criteria. The study population comprised 1,285 patients with a mean disease prevalence of 44% (range 22-63%). Sensitivity for the detection of CRC was 100%. Significant heterogeneity was found for overall per patient sensitivity and specificity. For polyps with a size of 10 mm or larger, per patient sensitivity and specificity estimates were 88% (95% CI 63-97%; I (2) = 37%) and 99% (95% CI 95-100%; I (2) = 60%). On a per polyp basis, polyps of 10 mm or larger were detected with a sensitivity of 84% (95% CI 66-94%; I (2) = 51%). The data were too heterogeneous for polyps smaller than 6 mm and 6-9 mm.

CONCLUSION: MR-colonography can accurately detect colorectal polyps more than 10 mm in size.