Blood flow dynamics after laser therapy of port wine stain birthmarks

Abstract

Background and Objective During laser therapy of port wine stain (PWS) birthmarks, regions of perfusion may persist. We hypothesize that such regions are not readily observable even when laser surgery is performed by highly experienced clinicians. The objective of this study was to use objective feedback to assess the acute vascular response to laser therapy. Study Design/Materials and Methods A clinic-friendly laser speckle imaging (LSI) instrument was developed to provide the clinician with real-time images of blood flow during laser therapy. Images were acquired from patients undergoing laser therapy of PWS birthmarks at Scripps Clinic and the Beckman Laser Institute and Medical Clinic. Blood flow maps were extracted from the acquired imaging data. Histogram-based analysis was applied in grading the degree of heterogeneity present in the blood flow maps after laser therapy. Results Collectively, two types of patient responses were observed in response to laser exposure: (1) an immediate increase in perfusion within minutes after laser therapy; and (2) an overall decrease in blood perfusion ~1 hour after laser therapy, with distinct regions of persistent perfusion apparent in the majority of post-treatment blood-flow images. A comparison of blood flow in PWS and adjacent normal skin demonstrated that PWS blood flow can be greater than, or sometimes equivalent to, that of normal skin. Conclusion In general, a decrease in skin perfusion is observed during pulsed laser therapy of PWS birthmarks. However, a heterogeneous perfusion map was frequently observed. These regions of persistent perfusion may be due to incomplete photocoagulation of the targeted vessels. We hypothesize that immediate retreatment of these regions identified with LSI, will result in enhanced removal of the PWS vasculature.

The Role of Laser Speckle Imaging in Port-Wine Stain Research: Recent Advances and Opportunities

“…With LSI measurements collected before and after laser therapy, we identified that regions of persistent perfusion oftentimes existed after treatment [121, 122]. We postulated that immediate re-treatment of these regions would lead to an improved treatment response, which then would result in a decrease in the number of required treatment sessions to achieve complete PWS blanching.…”

Monitoring blood volume fraction and oxygen saturation in port-wine stains during vascular targeted photodynamic therapy with diffuse reflectance spectroscopy: Results of a preliminary case study

“…To date, laser Doppler perfusion imaging [6], optical Doppler tomography [7], cross-polarized diffuse reflectance imaging [8], fluorescence spectroscopy [9], laser speckle imaging [10][11][12] and spatial frequency domain imaging [13] have been used in attempting to predict or determine the therapeutic efficacy of photodynamic or laser treatments of PWS. In comparison to the above mentioned techniques, diffuse reflectance spectroscopy (DRS) with a fiber-optic probe can non-invasively quantify the optical properties of biological tissues and has demonstrated its great potential as a cost-effective, fast and sensitive tool for tissue diagnosis and monitoring in medical clinics [14][15][16].…”

Handheld, point-of-care laser speckle imaging

“…[1][2][3][4] Researchers have used LSI in a variety of pilot clinical tests to monitor local blood-flow changes. [5][6][7] However, LSI is not used for routine hemodynamic monitoring in the clinic, mainly due to a lack of standardized instrumentation. We and other groups previously demonstrated that a mounted LSI device with sensitivity to blood-flow dynamics can be created with the use of inexpensive, consumer-grade electronics.…”