Color information from linked color imaging is associated with invasion depth and vascular diameter in superficial esophageal squamous cell carcinoma

Objectives: Accurate diagnosis of invasion depth is important for reliable treatment of esophageal squamous cell carcinoma (ESCC), but it is limited to the muscularis mucosae to slight submucosal invasion (MM/SM1). The diagnostic accuracy of invasion depth is unsatisfactory and remains to be improved. We aimed to investigate the association between the color of the superficial ESCC and invasion depth using linked color imaging (LCI) under light-emitting diode (LED) light sources. Methods: Lesions diagnosed as superficial ESCC were observed using white light imaging and then by LCI. The color values were calculated using Commission Internationale de l'Eclariage – L*a*b* color space, and the color difference was calculated according to invasion depth. The vascular diameters and vascular angles of the intrapapillary capillary loops were pathologically analyzed. Their correlation with mucosal color was also investigated by LCI. Results: In all, 52 lesions from 48 patients were analyzed. On the basis of invasion depth, the color difference between the normal mucosa and the lesion was larger in the MM/SM1 or deeper group than in the epithelium and the lamina propria mucosa (EP/LPM) group using LCI (P = 0.025). The vascular diameter was positively correlated with the b* color value (correlation coefficient = 0.302, P = 0.033). Conclusion: Observation using LCI under LED light sources may improve the endoscopic diagnosis of the invasion depth of superficial ESCC. Further research is needed to validate its usefulness. (UMIN000024615).