Image Processing Method for Visualizing White Zone in Magnifying Endoscopy with Narrow-Band Imaging of Gastric Mucosa

White zone visualized by magnifying endoscopy with narrow-band imaging （M-NBI） corresponds to stratified alignments of the gastric epithelium. In this study, we develop an image processing method for white zone with high sensitivity. Eleven specimens of endoscopic submucosal resection from 8 patients with gastric cancer were used. M-NBI was taken serially along the line of interest. The pictures were processed by low-pass filter for white zone area （%）, and visually classified into the presence （WZ+） or absence of white zone （WZ-） by a single endoscopist. The formalin-fixed-specimen was sliced along the same line of interest. The histological pictures was processed for averaged epithelial area（ μm×mm） at 1mm intervals. A total of 123 intervals were analyzed. In cancer, 36 intervals were visually classified as WZ- and 30 as WZ+. Averaged epithelial area and white zone area were significantly lower in WZ- than in WZ+. But, in background, two variables did not significantly differ between WZand WZ+. A total of 117 intervals had averaged epithelial area > 20 μm×mm and white zone area > 21.0 % with no correlation between two variables. Low-pass filter was found to visualize white zone in 41 intervals classified as WZ-