Noninvasive blood flow mapping for surgical guidance of vascular birthmarks

Port-wine stain (PWS) birthmarks are progressive capillary malformations which occur typically on the face or neck. To treat these birthmarks, the standard protocol involves use of pulsed laser light. The intent of this protocol is to heat selectively and coagulate the PWS vasculature. Patient response to laser therapy, remains highly variable and somewhat unpredictable. Our central hypothesis is that regions of the PWS vasculature are not photocoagulated, and that this incomplete stoppage of blood flow facilitates ensuing angiogenesis and hence revascularization of the skin with the abnormal PWS blood vessels. The long-term objective of our research is to determine the efficacy of image-guided retreatment of PWS skin. We have used the method of laser speckle imaging (LSI) to generate maps of skin blood flow before and after laser therapy. Based on prior experience with our first-generation LSI instrument, we have concluded that the clinical impact of LSI would be maximized only if a true intraoperative LSI instrument could be engineered. This instrument would need to satisfy the following design criteria: 1) real time and 2) nonintrusive.In summary, we now possess a clinic-ready imaging instrument which provides the treating clinicians with instantaneous feedback during the laser surgery session. We now are well poised to determine the degree to which immediate re-treatment affects the clinical outcome of laser treatment of PWS birthmarks.