Abstract

Background/Aims: Narrow band imaging (NBI) is a new technique that is expected to improve the detection rate of colorectal polyps, but results have been inconsistent. The aim of this study was to compare the polyp miss rate and the characteristics of missed colorectal polyps using white light (WL) and NBI.

Methods: 62 patients were randomized into two groups. In the first group (NBI first, NBIF), a colonoscopic examination of each segment (cecum-ascending, transverse, descending, and rectosigmoid colons) was performed first with NBI followed by a re-examination of the same segment using WL. An opposite sequence was applied for the other group (white light first, WLF).

Results: 67 polyps were found in the first examination, and 31 polyps were found on the re-examination, resulting in a polyp miss rate of 31.6%. The polyp miss rate was 39% for WLF and 23% for NBIF (p＞0.05). Seventy-four small polyps (＜5 mm) were found, and miss rates for NBIF and WLF were 20% and 46%, respectively (p=0.01). The polyp miss rate at the rectosigmoid was 11% for NBIF and 54% for WLF (p=0.01).

Conclusions: The polyp miss rate was not significantly different between NBI or WL when a colonoscopy was performed. NBI resulted in a lower polyp miss rate for small (＜5 mm) and rectosigmoid polyps than WL. (Korean J Gastrointest Endosc 2011;42:152-156)

• Keywords: Narrow band imaging, Polyp, Miss rate, Virtual chromoscopy