BACKGROUND: The endoscopic diagnosis of depressed-type early gastric cancers is difficult because these cancers manifest as subtle changes in color and shape. The newly developed optimal band imaging (OBI) system can reconstruct the best spectral images derived from ordinary endoscopic images and enhances the mucosal surface without the use of dyes. This imaging technique is based on narrowing the bandwidth of conventional image arithmetically by using spectral estimation technology. OBJECTIVE: Evaluation of the usefulness of the OBI system for identifying the demarcation line of depressed-type early gastric cancers. DESIGN: Prospective study. SETTING: Jichi Medical University in Japan. PATIENTS: Twenty-seven cases with depressed-type early gastric cancer. MAIN OUTCOME MEASUREMENT: Comparative study for the success rate of identifying the demarcation line of depressed-type early gastric cancer by using optimal band images and conventional endoscopic images. RESULTS: Demarcation of the depressed-type early gastric cancer was easily identified by optimal band images without magnification in 26 of 27 cases (96%), because distinct demarcation was observed endoscopically between the reddish images of the cancerous lesion and the yellowish images of the surrounding noncancerous area. With 40-fold magnification of optimal band images, the demarcation was also clearly recognized in all cases. Medical students could point out the demarcation line with significantly greater accuracy by observing the new nonmagnified optimal band images than by the conventional images (P< .0001). LIMITATION: Small sample size. CONCLUSIONS: The new contrasting images of the OBI system can delineate the depressed-type early gastric cancer more easily than conventional endoscopy.
BACKGROUND: The endoscopic diagnosis of depressed-type early gastric cancers is difficult because these cancers manifest as subtle changes in color and shape. The newly developed optimal band imaging (OBI) system can reconstruct the best spectral images derived from ordinary endoscopic images and enhances the mucosal surface without the use of dyes. This imaging technique is based on narrowing the bandwidth of conventional image arithmetically by using spectral estimation technology. OBJECTIVE: Evaluation of the usefulness of the OBI system for identifying the demarcation line of depressed-type early gastric cancers. DESIGN: Prospective study. SETTING: Jichi Medical University in Japan. PATIENTS: Twenty-seven cases with depressed-type early gastric cancer. MAIN OUTCOME MEASUREMENT: Comparative study for the success rate of identifying the demarcation line of depressed-type early gastric cancer by using optimal band images and conventional endoscopic images. RESULTS: Demarcation of the depressed-type early gastric cancer was easily identified by optimal band images without magnification in 26 of 27 cases (96%), because distinct demarcation was observed endoscopically between the reddish images of the cancerous lesion and the yellowish images of the surrounding noncancerous area. With 40-fold magnification of optimal band images, the demarcation was also clearly recognized in all cases. Medical students could point out the demarcation line with significantly greater accuracy by observing the new nonmagnified optimal band images than by the conventional images (P< .0001). LIMITATION: Small sample size. CONCLUSIONS: The new contrasting images of the OBI system can delineate the depressed-type early gastric cancer more easily than conventional endoscopy.