Histological analysis of the dermal and hypodermal layers of the face and correlation with high-frequency 24 MHz ultrasonography and elastosonography

Knowledge of the structure of the face is of fundamental importance. In fact, the face is treated in many areas of medicine, from dermatology, to maxillofacial, to ENT, to ophthalmology, etc. and anti-aging aesthetic treatments, and those for the resolution of blemishes are on the increase. For ethical reasons it is not possible to take biopsy samples for facial analysis in the aesthetic field. The main aim of this study was to demonstrate that a high-resolution bimodal ultrasound examination, combined with elastosonography, could be a valid tool for pre-treatment morphological evaluation. To achieve this goal, skin samples were taken from the forehead, zygomatic area, nasolabial fold, upper and lower lip from cadavers to histologically characterize their structure. Subsequently, these same areas were evaluated in vivo using conventional B-mode ultrasound with a 24 MHz high-frequency probe, and elastosonography. The data obtained with the different techniques were compared, in order to state that modern ultrasound techniques can provide similar histological information. The analysis showed that the superficial hypodermis presented a different shape and structure in the different areas, with the exception of the areas of the upper and lower lip, which appeared similar. With aging, the forehead and zygomatic area showed a volumetric increase in the superficial hypodermic layer, while the lip showed non-structural changes. The morphology of the nasolabial fold remained unchanged. When it is not possible to perform histological investigations on the face, to understand its characteristics and dynamics, ultrasound with a 24 MHz probe would seem to be the most suitable method, while elastosonography could be a valid method for evaluating the stiffness of the structural components.