Usefulness of third-generation narrow band imaging and texture and color enhancement imaging in improving visibility of superficial early gastric cancer: A study using color difference.

OBJECTIVES: Overlooking early gastric cancer (EGC) during endoscopy is an issue to be resolved. Image-enhanced endoscopy is expected to improve EGC detection. This study investigated the usefulness of third-generation narrow band imaging (3G-NBI) and texture and color enhancement imaging (TXI) in improving the visibility of EGC using the color difference between EGC and its surrounding gastric mucosa.

METHODS: In this retrospective observational study, we examined 51 superficial EGCs that underwent endoscopic submucosal dissection and were observed by all three methods: 3G-NBI, TXI, and white light imaging (WLI). The primary endpoint was to compare the color difference of each method. For each EGC, we prepared one non-magnifying image for each method so that the location and size of the lesion in each image were the same. The L*a*b* color space was used to evaluate the color values. When the color values of the cancerous lesion and its surrounding mucosa were (L*c , a*c , b*c ) and (L*s , a*s , b*s ), respectively, the color difference was defined to be [(L*c -L*s )2 +(a*c -a*s )2 +(b*c -b*s )2 ]1/2 .

RESULTS: The median color difference was 9.2 (interquartile range, 5.3-15.7) in WLI, 13.5 (interquartile range, 9.4-19.5) in 3G-NBI, and 15.3 (interquartile range, 9.1-22.1) in TXI. Statistically, the color difference was significantly larger in 3G-NBI than in WLI ( p < 0.001) and TXI compared with WLI ( p < 0.001). However, there was no significant difference between 3G-NBI and TXI ( p = 0.330).

CONCLUSIONS: Regarding color difference, both 3G-NBI and TXI were estimated to be more useful than WLI in improving the visibility of superficial EGC.