Endoscopy system and setting

The endoscopy system consisted of a video processor (CV-260SL; Olympus Co., Tokyo, Japan) and a light source (CLV-260SL; Olympus Co.) that worked in both the high-resolution white-light imaging and NBI modes. NBI illuminates narrow-banded short-wavelength light (400 – 430 and 525 – 555 nm) to contrast the vascular architecture and surface structure of the superficial mucosa ⁶ . Magnifying endoscopy that can achieve a maximum 80-fold optical magnification was used (GIF-Q240Z, GIF-H260Z, and GIF-FQ260Z; Olympus Co.). A soft black hood (MB162 or MB46; Olympus Co.) was attached to the tip of the endoscope to enable the endoscopist to maintain an adequate distance for maximal magnification of the endoscopic image. The structural enhancement of the endoscopic video processor was set to B-mode level 4 or 6 for white-light endoscopy and to B-mode level 8 for M-NBI. The color mode was set at level 1.