Age-related changes in elastographically determined strain of the facial fat compartments: a new frontier of research on face aging processes

Introduction
Our study goal was verification of shear-wave elastography (SWE) as an assessment tool enabling quantitative analysis of facial fat tissue elasticity, using the example of the deep medial cheek fat compartment (DMCFC), due to its major role in pseudoptosis etiology.

Aim
Furthermore, we determined the age-specific reference values for DMCFC elasticity and analyzed its correlation with body mass index (BMI) and DMCFC thickness.

Material and methods
The study included 89 female patients (age: 18–63 years, mean: 45.9 ±14.2 years) with intact facial skin. Prior to the procedure, all participants were subjected to SWE of the DMCFC. Reference ranges for elastographic parameters were defined as ± 2 standard deviations (SD), or estimated by means of ROC analysis.

Results
The DMCFC elasticity correlated inversely with DMCFC thickness (R = –0.292, p < 0.001), age (R = –0.838, p < 0.001) and BMI of the study subjects (R = –0.258, p = 0.001). Age was found to be the only independent determinant of DMCFC elasticity on multiple linear regression analysis (b = –0.837, p < 0.001). The cut-off values for DMCFC elasticity estimated during ROC analysis provided excellent accuracy in distinguishing between women from various age categories, and to a large degree overlapped with the reference intervals defined as ± 2 SD.

Conclusions
Shear-wave elastography enables quantitative evaluation of facial fat pad elasticity, creating a new frontier in research on age-related processes. The results indicate that elasticity of the DMCFC decreases significantly with age. Tissue elasticity might be an indirect indicator of metabolic and structural properties of facial adipose tissue and its extracellular matrix.