Volumetric Changes of the Mid and Lower Face with Animation and the Standardization of Three-Dimensional Facial Imaging.

Abstract

The objective of this study was to quantify volumetric changes of the mid and lower face caused by facial expression to understand how procedural results measured by three-dimensional imaging can be influenced by lack of standardization. Secondarily, the study identified soft-tissue surface landmarks that can be used to ensure the standardization of three-dimensional images. Three-dimensional facial images of subjects performing 22 facial expressions or changes in head position were captured. Variable degrees of animation during smiling and frowning were also evaluated. Volumetric changes of the malar and jowl regions were quantified using a three-dimensional superimposed image subtraction technique. The translation of 14 standard soft-tissue surface landmarks was assessed during various facial animations to determine which three-dimensional landmarks can be used to standardize three-dimensional images. Twenty subjects participated in the study. Sixteen of the 22 facial expression studies had a significant effect on malar and/or jowl volume. Significant volume changes were noted with subtle animation during smiling and frowning. A combination of five landmarks (i.e., glabella, bilateral cheilion, pogonion, and laryngeal prominence) can be used to standardize three-dimensional images for evaluation of mid and lower facial volume changes. Subtle facial expressions may cause significant volumetric changes in the mid and lower face that can mimic the desired outcomes of surgical and nonsurgical facial rejuvenation procedures. The five-point referencing system allows one to identify subtle changes in head position and facial expression and may aid in the standardization of three-dimensional images.