Gniadecka M, Quistorff B
Department of Dermatology, University of Copenhagen, Denmark.
Br J Dermatol. 1996 Aug;135(2):218-24.
Although a principal constituent of human skin, cutaneous water is difficult to study, and little is known about water behaviour in physiological and pathological conditions of the skin. It has been proposed recently that changes in dermal echogenicity measured by high-frequency ultrasonography reflect changes in dermal water content. To validate skin ultrasonography for assessment of dermal water changes we have studied the relationship between dermal echogenicity and skin water content determined by nuclear magnetic resonance technique. Twenty MHz ultrasound scanning of the dorsal and ventral forearm skin was performed in 59 healthy volunteers (age 18-65) and dermal echogenicity was determined by counting low echogenic pixels (LEPs) in skin images. 1H magnetic resonance spectra were obtained from the same regions and the ratio of areas under the water- and fat-specific peaks (W/F) were calculated to measure a relative water content. Acute dermal oedema (histamine weal) was studied in the same way in 40 individuals. Baseline dermal echogenicity correlated significantly with W/F, both in the ventral (r = 0.47) and dorsal (r = 0.57) forearm. Intradermal application of histamine caused a development of intradermal oedema which could be visualized by nuclear magnetic resonance imaging. In a corresponding ultrasound image oedema was seen as a low-echogenic area. The proportional increases in LEPs and W/F after histamine application were correlated, but the elevation in LEPs was 25-48% (95% confidence intervals) higher than that for W/F. These results suggest that high-frequency ultrasonography is a sensitive method for assessment of changes in dermal hydration. This technique may find important applications in comparative and non-invasive evaluations of dermal water in physiological conditions and in skin pathologies associated with oedema formation.
尽管皮肤水分是人体皮肤的主要成分，但很难对其进行研究，而且对于皮肤在生理和病理状态下的水分行为知之甚少。最近有人提出，通过高频超声测量的真皮回声性变化反映了真皮含水量的变化。为了验证皮肤超声检查对评估真皮水分变化的有效性，我们研究了通过核磁共振技术测定的真皮回声性与皮肤含水量之间的关系。对59名健康志愿者（年龄18 - 65岁）的前臂背侧和腹侧皮肤进行了20兆赫的超声扫描，并通过计算皮肤图像中的低回声像素（LEP）来确定真皮回声性。从相同区域获得了氢磁共振光谱，并计算了水峰和脂肪峰下面积的比值（W/F）以测量相对含水量。对40名个体以同样的方式研究了急性真皮水肿（组胺风团）。在腹侧（r = 0.47）和背侧（r = 0.57）前臂，基线真皮回声性与W/F均显著相关。皮内注射组胺导致皮内水肿的形成，这可以通过核磁共振成像观察到。在相应的超声图像中，水肿表现为低回声区域。组胺注射后LEP和W/F的比例增加具有相关性，但LEP的升高比W/F高25 - 48%（95%置信区间）。这些结果表明，高频超声检查是评估真皮水合作用变化的一种敏感方法。该技术可能在生理条件下以及与水肿形成相关的皮肤病理学中真皮水分的比较和非侵入性评估方面找到重要应用。
