Quantitative evaluation of atrophic acne scars using 3D image analysis with reflected LED light.

Background: Methods for objective evaluation of acne scars have not been established yet. In this study, the capability of three-dimensional image analysis of acne scarring was examined. Methods Two dermatologists evaluated the severity and counted the number of atrophic acne scars in a defined evaluation area of each cheek (3.5 cm x 3.5 cm) of 22 subjects (age, 21-38 years). Images of the evaluation area were obtained with an Antera 3D (R) (Miravex Limited, Ireland) camera three times, and three parameters (affected area, volume, and max depth) were measured. Three different filters (small, medium, and large), which limit measurement targets based on the diameters of concavities, were used for measurement. The relationships between each parameter and the evaluation results of scars by dermatologists were analyzed using Spearman's correlation coefficients. Results The correlations between the evaluation results of scars by dermatologists and each parameter measured were the highest when the large filter was used. The correlation coefficients between the severity of scars by dermatologists and each of affected area, volume, and max depth were 0.736, 0.728, and 0.722, respectively, and those between scar counts and each of affected area and volume were 0.783 and 0.770, respectively. The correlations, scatter plots, and regression lines among three measurements of parameters suggested high repeatability. Conclusions Three-dimensional image analysis has the capability to evaluate changes in the shape of scars before and after treatment quantitatively.