Narrow band imaging in the detection of colorectal polyp: Korean experience

Abstract

Background: Although white light (WL) colonoscopy is a gold standard to detect colorectal polyps, substantial polyps are missed. Narrow band imaging (NBI) is a new technology that enables a more detailed visualization of the mucosal surface. The aim of the present study was to determine whether NBI can improve the detection of colorectal polyps. Methods: We prospectively enrolled 188 (M : F = 99:89, 21-80 years) subjects undergoing colonoscopy as a screening procedure in nine referral centers. After a careful WL examination of the whole colorectum, rectosigmoid colon (0-30 cm from the anal verge) was reobserved by NBL Size, macroscopic morphology, and the histology of all the polyps detected during WL and NBI examination were analyzed. Results: WL examination detected 162 polyps in 188 subjects, of which 106 lesions were neoplastic, while NBI of rectosigmoid colon detected an additional 61 polyps of which eight lesions were neoplastic. Only 10 (6.2%) of 162 polyps discovered during WL examination were flat polyps compared to 10 (16.4%) of 61 newly detected polyps during NBI being flat type (P = 0.002). The mean polyp size detected by NBI was smaller than that found by WL colonoscopy (2.8 +/- 1.0 mm vs 6.5 +/- 4.5 mm, P < 0.001). Conclusion: Many additional colorectal polyps, especially flat type, could be detected by NBI examination for normal-looking rectosigmoid mucosa. The role of NBI in colorectal neoplasm screening needs to be further investigated in future studies.