Abstracts

AIM: It is expected that the detection of early gastric cancer (EGC) is improved by image enhanced endoscopy including Narrow band imaging (NBI) and Texture and color enhancement imaging (TXI).This study aimed to investigate the usefulness of NBI and TXI in improving the visibility of superficial EGC using color difference.METHODS: Among EGCs that underwent endoscopic submucosal dissection between August 2020 and March 2021, we examined 51 superficial EGCs which were observed by all of the three observation methods, NBI, TXI, and white light imaging (WLI).For each lesion, we selected one non-magnifying image for each method so that the location and size of the lesion in the three images were the same.The lesion boundaries in the images were determined based on the results of magnifying NBI and pathology.The L*a*b* color space was used to evaluate the hue.When the color values of the lesion and the background gastric 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 .We compared the color differences obtained by the three methods. RESULTS:The lesion location (U/M/L/gastric remnant) was 20/ 20/10/1, macroscopic type (IIa/IIb/IIc) was 17/1/33, the median tumor size was 13 mm, histopathology (differentiated/undifferentiated) was 47/4, resection depth (pT1a/pT1b) was 45/6, and endoscopic gastric atrophy (with/without) was 49/2.The mean color difference was 10.9 in WLI, 15.1 in NBI, and 15.9 in TXI.Statistically, the color difference was significantly larger in NBI than in WLI (P < 0.005) and so was it in TXI than in WLI (P < 0.005).On the other hand, there was no significant difference between NBI and TXI (P = 0.327). CONCLUSIONS:In terms of the color difference, both NBI and TXI were estimated to be more useful than WLI in improving the visibility of superficial EGC.