Measurement and comparison of facial skin thickness by ultrasonography and 3D scanner

Abstract

Three-dimensional (3D)-scanning-based morphological studies of the face are commonly included in various clinical procedures. This study evaluated validity and reliability of a 3D scanning system by comparing the ultrasound (US) imaging system versus the direct measurement of facial skin. The facial skin thickness at 19 landmarks was measured using the 3 different methods in 10 embalmed adult Korean cadavers. Skin thickness was first measured using the ultrasound device, then 3D scanning of the facial skin surface was performed. After the skin on the left half of face was gently dissected, deviating slightly right of the midline, to separate it from the subcutaneous layer, and the harvested facial skin’s thickness was measured directly using neck calipers. The dissected specimen was then scanned again, then the scanned images of undissected and dissected faces were superimposed using Morpheus Plastic Solution (version 3.0) software. Finally, the facial skin thickness was calculated from the superimposed images. The intraclass correlation coefficient value for the correlations between the 3D scanning system and direct measurement showed excellent reliability (0.849, 95% confidence interval = 0.799–0.887). Bland-Altman analysis showed a good level of agreement between the 3D scanning system and direct measurement (bias = 0.49±0.49 mm, mean±SD). These results demonstrate that the 3D scanning system precisely reflects structural changes before and after skin dissection. Therefore, an in-depth morphological study using this 3D scanning system could provide depth data about the main anatomical structures of face, thereby providing crucial anatomical knowledge for utilization in various clinical applications.