Objective interpretation of severity of SLS induced edema by stereoimaging

Background: In the evaluation of the severity of skin inflammations, visual scoring system is widely being used as a subjective method. However, it is well known that interobserver variations occur even between the interpretations of experienced dermatologists. Objective: To develop a new objective and quantitative method for the evaluation of skin surface contours and for the assessment of severity in SLS-induced edema, a new investigatory tool. based on the concept of "stereoimaging" was studied. Differences between binocular images were used by a stereoimage optical topometer (SOT) system capable of calculating skin surface topographic information, which was then used to produce a three-dimensional image. Methods: We compared the results obtained by SOT with a visual scoring system after applying sodium lauryl sulfate (SLS) to skin. The degree of edema was assessed qualitatively by visual scoring (0: none, 1: mild edema, 2: moderate edema, 3: severe edema). To quantify the severity, five three-dimensional parameters (Sa, S-Z, SL, SA and SV) were used in the SOT analysis. Results: The means of these five parameters increased significantly in visual grade 1 + compared to visual grade 0 and the means of the five parameters decreased significantly and proportionally as the visual grades increased from 1 + to 3+. A highly significant correlation was found to exist between the visual scoring results and the five SOT parameters. Conclusion: SOT can be used to evaluate the severity of SLS-induced edema objectively and can be extensively applied to evaluate the degree of severity in other inflammatory skin conditions. (C) 2004 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.