Background/Aim: To evaluate diagnostic accuracy of MR colonography without bowel cleansing in a screening population and compare results to colonoscopy as standard of reference.
Methods: 315 screening patients older than 50 years with normal risk profile for colorectal cancer were included in this study. For MR colonography, a tagging agent (5.0% Gastrografin, 1.0% Bariumsulfate, 0.2% Locust bean gum) was ingested with each principal meals within two days prior to MR colonography. No bowel cleansing was applied. For the MR examination a rectal water enema was administered. Data collection was based on contrast enhanced T1w images and TrueFISP images. MR data were analyzed concerning image quality and presence of colorectal lesions. Conventional colonoscopy and histopathological samples served as standard of reference.
Results: In 4% of all colonic segments, MR image quality was insufficient due to non-tagged fecal material. Adenomatous polyps >5mm were detected by means of MR colonography with a sensitivity of 83.0%. Over-all specificity amounted to 90.2% (false positive findings in 19 patients). However, only 16 out of 153 lesions <5mm and 9 out of 127 hyperplastic polyps could be visualized on MR images.
Conclusions: Fecal tagging MR colonography is applicable for screening purposes. It provides a good accuracy for the detection of relevant, i.e. adenomatous colorectal lesions >5mm in a screening population. However, refinements to optimize the image quality of fecal tagging are needed.
- adenomatous colorectal lesions
- diagnostic accuracy
- fecal tagging
- magnetic resonance colonography
- population based