Objective Evaluation of Sublingual Veins Using Color Differences

색차(色差)값을 활용(活用)한 설하락맥(舌下絡脈)의 정량적(定量的) 평가(評價)

Background: Although several efforts have been made recently to grade the severity of sublingual veins, these methods still meet some problems: clinicians' subjectivity and diversity of lighting conditions. Objectives: The purpose of our study was to quantify the severity of sublingual veins using CDs (color differences), and to verify clinical validity of the parameters of sublingual veins using CDs. Methods: We photographed the inferior surface of subjects' tongue from 74 subjects. CDs were computed through two sets of mean $L^*a^*b^*$ values extracted from BRC (black reference color) and the inferior surface of the tongue. We assumed that SVI (sublingual veins index) normalized percentage of a reciprocal of CDs between BRC and the inferior surface of the tongue including sublingual veins and BISV (black index of sublingual veins) percentage of a reciprocal of CDs between BRC and the main trunk of sublingual veins could be applied as quantitative parameters of sublingual veins and examined whether there are meaningful correlations between CDs and subjective grading by the clinicians or not. Results: There were high positive correlations of SVI and BISV to clinician evaluation respectively (r=0.715, 0.634). We computed a multiple regression equation which includes SVI and BISV as independent factors $(r^2=0.60);\;Y=0.711+0.046X_1+0.205X_2$ (Y: the severity of sublingual veins, $X_1:\;SVI,\;X_2:\;BISV$). Conclusions: We conclude that the severity of sublingual veins can be quantified through SVI and BISV, minimizing the clinicians' subjectivity and the diversity of lighting conditions.