| [ Summary ] |
Screening for superficial colorectal tumors has evolved over time with advances in endoscopic technology. Conventional white-light imaging (WLI) is being increasingly replaced with image-enhanced endoscopy (IEE) with narrow-band imaging (NBI) as the mainstay for screening. A comparison between WLI and NBI shows the superiority of NBI over WLI in detecting non-granular type (LST-NG) tumors. Depressed and reactive elevated areas of depressed tumors are visualized as whitish and brownish, with NBI. Together they constitute the so-called "O-ring sign" characteristic of NBI findings for depressed tumors. On the other hand, a prospective screening for cecal diminutive adenomas alone sequentially with WLI, NBI, and chromoendoscopy (indigo carmine dye spraying) showed that cecal dimutive adenomas were detected most frequently with chromoendoscopy, followed by NBI and WLI (47, 37 and 11 lesions, respectively) suggesting the usefulness of chromoendoscopy. Thus, while NBI appears to represent the mainstay for pan-colonic screening at present, further refinements in IEE are required to improve chromoendoscopy with pan-colonic screening. |