TISSUE PARAMETERS DETERMINING THE VISUAL APPEARANCE OF NORMAL SKIN AND PORT-WINE STAINS

Port-wine stain is a congenital birthmark consisting of an abnormal density of blood vessels in the upper dermis. The enlarged blood volume gives the lesion a red to purple colour. The aim of the treatments is to destroy the vessels to the extent necessary for obtaining a normal skin coloration. Thus, in principle, all relevant information about the lesion should be contained in a reflectance spectrum in the visible. However, the relation between the reflectance spectrum and tissue parameters such as scattering, melanin content and blood distribution is somewhat composite. This work tries to enlighten this relation in terms of a very simple analytical mathematical model, and it is demonstrated that such a model at least will contribute to a qualitative understanding of the relevance of the various parameters.