Detection of skin thickness and density in healthy Chinese people by using high-frequency ultrasound.

Objectives: Due to a recent development of high-frequency ultrasound (HFUS) systems, it is easier to realize high-resolution in vivo imaging of the biological tissues. The object of this study was to map the thickness and echo density of skin layers in healthy Chinese people and assess the influence of gender, age, and region on it.

Methods: A total of 189 volunteers (85 male, 104 female) with age range of 22-75-year old (mean age of 41.2-year old) were enrolled. The thickness and density of the epidermis and dermis layer were detected by high-frequency (22 or 75 MHz) ultrasonography at 13 different anatomical sites, including the forehead, cheeks, flexor and extensor forearms, flexor and extensor upper arms, inner and outer legs, inner and outer thighs, back, and abdomen.

Results: The thickness and density of epidermis/dermis between different anatomical sites were statistically significant (p < 0.05). The epidermis thickness of the face and trunk were less than that of the limbs, whereas the thicknesses of the dermis were on the contrary. The density of the epidermis/dermis of the face and trunk were less than that of the limbs. The thickness of dermis in most of the sites were higher in male than in female, and the density of epidermis and dermis in most of the sites were less in men than in women. The thicknesses/densities of dermis were lower in older age group in almost all sites, whereas only several sites reached statistical. The difference between the north and south regions showed the environment also influenced the thickness and density of the skin.

Conclusion: HFUS provides a simple noninvasive method for evaluating the skin thickness and echo-density, which, reflecting intradermal structure, exhibit systematic regional variation. With the establishment of Chinese phenotypic database of skin thickness and density, it will be helpful for the skin disease assessment, skin surgery, and cosmetology technology.