Arsalan Mazhar

Port-wine stain birthmarks are one class of benign congenital vascular malformation. Laser therapy is the most successful treatment modality of PWS. Unfortunately, this approach has limited efficacy, with only 10% of patients experiencing complete blanching of the PWS. To address this problem, several research groups have developed technologies and methods designed to study treatment outcome and improve treatment efficacy. This article reviews seven optical imaging techniques currently in use or under development to assess treatment efficacy, focusing on: reflectance spectrophotometers/tristimulus colorimeters; laser Doppler flowmetry and laser Doppler imaging; cross-polarized diffuse reflectance colour imaging system; reflectance confocal microscopy; optical coherence tomography; spatial frequency domain imaging; and laser speckle imaging. © 2012 The Authors. BJD © 2012 British Association of Dermatologists 2012.

Background and Objective Objective methods to assess port wine stain response to laser treatment have been the subject of various research efforts for several years. Herein, we present a pilot study using a newly developed, light emitting diode based spatial frequency domain imaging device to record quantitatively biochemical compositional changes in PWS after laser therapy. Study Design/Patients and Methods A SFDI system was used to image before, and after, five PWS treatment sessions [n = 4 subjects ]. SFDI derived wide-field optical properties and tissue chromophore concentrations including oxy-hemoglobin, deoxy-hemoglobin, total hemoglobin, and tissue oxygen saturation are presented for skin imaged prior to and immediately after laser treatment. The SFDI derived images were analyzed by comparing the above measurements in PWS to those of normal skin and tracking changes immediately after laser exposure. Results Elevated oxy-hemoglobin and tissue oxygen saturation were measured in all PWS lesions and compared to values for normal skin prior to treatment. Laser treatment resulted in an increase in deoxy-hemoglobin, decrease in tissue oxygen saturation, and reduced scattering in all PWS lesions. One subject was followed before and after two consecutive laser treatments and the overall improvement in PWS lesion blanching was quantitatively assessed by measuring a 45% decrease in dermal blood volume. Conclusion SFDI is a rapid non-contact wide-field optical technique that shows potential as an imaging device that can be used to quantify biochemical compositional changes in PWS after laser therapy. Future work will investigate the potential of SFDI to provide intra-operative guidance for laser therapy of PWS lesions on an individual patient basis. © 2012 Wiley Periodicals, Inc.

We describe a noncontact profile correction technique for quantitative, wide-field optical measurement of tissue absorption and reduced scattering coefficients, based on geometric correction of the sample's Lambertian reflectance intensity. Because the projection of structured light onto an object is the basis for both phase-shifting profilometry and modulated imaging, we were able to develop a single instrument capable of performing both techniques. In so doing, the surface of the three-dimensional object could be acquired and used to extract the object's optical properties. The optical properties of flat polydimethylsiloxane phantoms with homogenous tissue-like optical properties were extracted, with and without profilometry correction, after vertical translation and tilting of the phantoms at various angles. Objects having a complex shape, including a hemispheric silicone phantom and human fingers, were acquired and similarly processed, with vascular constriction of a finger being readily detectable through changes in its optical properties. Using profilometry correction, the accuracy of extracted absorption and reduced scattering coefficients improved from two- to ten-fold for surfaces having height variations as much as 3cm and tilt angles as high as 40deg. These data lay the foundation for employing structured light for quantitative imaging during surgery. © 2009 Society of Photo-Optical Instrumentation Engineers.