Background and study aims: Colonoscopy is widely used to detect and remove precancerous polyps, but fails to detect some polyps. Recent studies evaluating different image-enhanced methods have revealed conflicting results. The efficacy of colonoscopy imaging with simultaneous use of commercially available improvements, including high definition narrow band imaging (HD-NBI), and monochromatic charge-coupled device (CCD) video, was compared with a widely used standard definition white light (SDWL) colonoscopy system for detecting colorectal polyps. The primary aim was to determine whether the combination of image-enhanced colonoscopy systems resulted in fewer missed polyps compared with conventional colonoscopy. Patients and methods: In a randomized controlled trial (Clinicaltrials.gov. study number NCT00825292) patients having routine screening and surveillance underwent tandem colonoscopies with SDWL and image-enhanced (HD-NBI) colonoscopy. The main outcome measurement was the per-polyp false-negative (miss) rate. Secondary outcomes were adenoma miss rate, and per-patient polyp and adenoma miss rates. Results: 100 patients were randomized and 96 were included in the analysis. In total, 177 polyps were detected; of these, 72 (41%) were adenomatous. Polyp and adenoma miss rates for SDWL colonoscopy were 57% (60/105) and 49% (19/39); those for image-enhanced colonoscopy were 31% (22/72) and 27% (9/33) (P=0.005 and P=0.036 for polyps and adenomas, respectively). Image-enhanced and SDWL approaches had similar per-patient miss rates for polyps (6/35 vs. 9/32, P=0.27) and adenomas (4/22 vs. 8/20, P=0.11). Conclusions: Utilization of multiple recent improvements in image-enhanced colonoscopy was associated with a reduced miss rate for all polyps and for adenomatous polyps. It is not known which individual feature or combination of image-enhancement features led to the improvement.
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