Gniadecka M, Jemec G B
Department of Dermatology D92, Bispebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, 2400 Copenhagen, Denmark.
Br J Dermatol. 1998 Nov;139(5):815-21. doi: 10.1046/j.1365-2133.1998.02506.x.
Skin ageing is divided into chronological ageing and photoageing due to the cumulative effects of solar ultraviolet radiation. It is, however, difficult to measure the degree of photoageing and chronological ageing in humans in vivo. Here, we have evaluated the usefulness of ultrasonography for measurement of chronological ageing and photoageing in vivo. Twenty megahertz ultrasonography was performed in 90 individuals (29 men, 61 women, age 18-94) to describe age-related changes in sun-exposed regions with different levels of sun exposure (dorsal and ventral forearm, forehead, ankle) and non-exposed buttock skin. Skin thickness and skin echogenicity in different layers of the dermis were measured in ultrasound images. Additionally, cutaneous photodamage was scored clinically. Age-related changes were dependent on body site as well as layer of the dermis. A progressive, age-related decrease in echogenicity of the upper dermis was found in sun-exposed regions (dorsal forearm, forehead), but not in moderately exposed regions (ventral forearm, ankle). In the buttock an increase in echogenicity was observed. The echogenicity of the lower dermis increased in all examined sites. Skin thickness increased with age in the forehead and buttock, but decreased in the extremity skin. Our findings show that photoageing causes a decrease in echogenicity in the upper dermis. In contrast, chronological ageing is associated with an increase in echogenicity in the lower dermis. Although both increases and decreases in skin thickness were observed in different anatomical regions, there was no general relationship between skin thickness and age. Dermal echogenicity was deemed valuable for in vivo study of chronological ageing and photoageing.
由于太阳紫外线辐射的累积效应，皮肤老化分为自然老化和光老化。然而，在人体活体中难以测量光老化和自然老化的程度。在此，我们评估了超声检查在活体测量自然老化和光老化方面的实用性。对90名个体（29名男性，61名女性，年龄18 - 94岁）进行了20兆赫的超声检查，以描述不同日晒水平的暴露区域（前臂背侧和腹侧、前额、脚踝）以及未暴露的臀部皮肤与年龄相关的变化。在超声图像中测量真皮不同层的皮肤厚度和皮肤回声。此外，对皮肤光损伤进行临床评分。与年龄相关的变化取决于身体部位以及真皮层。在前臂背侧、前额等暴露区域发现上真皮回声随年龄增长逐渐降低，但在前臂腹侧、脚踝等中度暴露区域未发现这种情况。在臀部观察到回声增加。所有检查部位下真皮的回声均增加。前额和臀部的皮肤厚度随年龄增加，但四肢皮肤的厚度则下降。我们的研究结果表明，光老化会导致上真皮回声降低。相比之下，自然老化与下真皮回声增加有关。尽管在不同解剖区域观察到皮肤厚度有增有减，但皮肤厚度与年龄之间没有普遍的关系。真皮回声被认为对自然老化和光老化的活体研究具有重要价值。
