Ultrasonographic assessment of skin structure according to age.

BACKGROUND: High-frequency ultrasound is a noninvasive tool that offers characteristic markers, quantifying the cutaneous changes of the physiological senescence process. AIMS: The aim was to assess the changes in skin thickness, dermal density and echogenicity, as part of the ageing process, with different age intervals.
METHODS: The study was performed on 160 patients, aged 40.4 ± 21.2, divided into four age categories: <20, 21-40, 41-60, 61-80. Ultrasonographic images (Dermascan device) were taken from three sites: dorsal forearm (DF), medial arm (MA), zygomatic area (ZA). We assessed the thickness of epidermis and dermis (mm), number of low, medium, high echogenicity pixels, the ratio between the echogenicity of the upper and lower dermis (LEPs/LEPi), and SLEB (subepidermal low echogenicity band). The statistical analysis was performed using SPSS 15.00. A P value <0.05 was considered significant.
RESULTS: On all examined sites, it was found that the dermal thickness increases in the 21 to 40 year interval (P<0.0001). After the 21 to 40 year interval, the number of low echogenic pixels increases significantly, especially on photoexposed sites. High-echogenic pixels follow the same pattern on all examined sites: they increase in the 21 to 40 year interval and decrease in the 3rd and 4th age category. The LEPs/LEPi ratio increases significantly with age, at all sites (P<0.05), due to an increase of hypoechogenic pixels in the upper dermis.
CONCLUSIONS: High-frequency ultrasound is a noninvasive "histological" tool that can assess the cutaneous structure and age-related changes. It offers imagistic markers, comparable to the histological parameters and also characteristic ultrasonographic markers. Histology remains the gold standard for the investigation of the integumentary system.