Gabay S, Lucassen G W, Verkruysse W, van Gemert M J
Laser Centre, Academic Medical Centre, University of Amsterdam, The Netherlands.
Lasers Surg Med. 1997;20(2):179-87. doi: 10.1002/(sici)1096-9101(1997)20:2<179::aid-lsm9>3.0.co;2-n.
Laser treatment of port wine stains (PWS) has become an established clinical modality over the past decade. However, in some cases full clearance of the PWS cannot be achieved. To improve the clinical results, it is necessary to match the laser treatment parameters to the PWS anatomy on an individual patient basis. Therefore, knowledge of the PWS structure is of great importance. The objective of this study is to describe a diagnostic method to assess the PWS blood vessels depth and diameter from the skin surface temperature-time course following a diagnostic laser pulse.
STUDY DESIGN/MATERIALS AND METHODS: The Monte Carlo (MC) method was used to calculate the deposited laser energy into a port wine stain skin model following irradiation by a diagnostic laser pulse at 577 nm. The heat equation was solved numerically, using the deposited energy profile as the source term, yielding the temperature-time course at the skin surface. Subtraction of "bloodless" skin signal from that of the skin containing blood vessels gives us the net contribution of a heated dermal blood vessel to the skin surface temperature-time behaviour.
The net blood vessel signal shows heat-diffusion behaviour and was found to be sensitive to the dermal blood vessel depth and diameter. The time delay for the peak signal temperature to occur depends quadratically on the blood vessel depth. The peak temperature relates linearly to the blood vessel diameter. The degree of epidermal melanin content can also be determined from the immediate temperature rise of the signal.
The proposed method easily enables assessment of the blood vessel depth and diameter as well as the epidermal melanin content in a skin model. The method can be applied to a real PWS when using the adjacent normal skin as a reference.
在过去十年中，激光治疗鲜红斑痣（PWS）已成为一种成熟的临床治疗方式。然而，在某些情况下，鲜红斑痣无法完全清除。为了提高临床效果，有必要根据个体患者的情况使激光治疗参数与鲜红斑痣的解剖结构相匹配。因此，了解鲜红斑痣的结构非常重要。本研究的目的是描述一种诊断方法，通过诊断性激光脉冲后皮肤表面温度 - 时间过程来评估鲜红斑痣血管的深度和直径。
研究设计/材料与方法：采用蒙特卡罗（MC）方法计算在577 nm诊断性激光脉冲照射后，鲜红斑痣皮肤模型中沉积的激光能量。利用沉积的能量分布作为源项，对热方程进行数值求解，得出皮肤表面的温度 - 时间过程。从含有血管的皮肤信号中减去“无血”皮肤信号，可得到受热真皮血管对皮肤表面温度 - 时间行为的净贡献。
净血管信号呈现热扩散行为，且发现其对真皮血管深度和直径敏感。信号峰值温度出现的时间延迟与血管深度呈二次方关系。峰值温度与血管直径呈线性关系。表皮黑色素含量的程度也可从信号的即时温度升高来确定。
所提出的方法能够轻松评估皮肤模型中的血管深度和直径以及表皮黑色素含量。当以相邻正常皮肤作为参考时，该方法可应用于实际的鲜红斑痣。
