title: Blood flow dynamics after laser therapy of port wine stain birthmarks.
abstract: 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.
  
  
  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 approximately 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.
  
  
  CONCLUSIONS
  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. Lasers Surg. Med. 41:563-571, 2009. (c) 2009 Wiley-Liss, Inc.
authors.affiliation: Beckman Laser Institute and Medical Clinic, University of California, Irvine, California 92612, USA.
authors.forename: Yu-Chih
authors.initials: YC
authors.lastname: Huang
authors.forename: Nadia
authors.initials: N
authors.lastname: Tran
authors.forename: Peter R
authors.initials: PR
authors.lastname: Shumaker
authors.forename: Kristen
authors.initials: K
authors.lastname: Kelly
authors.forename: E Victor
authors.initials: EV
authors.lastname: Ross
authors.forename: J Stuart
authors.initials: JS
authors.lastname: Nelson
authors.forename: Bernard
authors.initials: B
authors.lastname: Choi
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D017078:Laser-Doppler Flowmetry; D054025:Lasers, Dye / Q000627:therapeutic use*; D028022:Low-Level Light Therapy; D008297:Male; D044085:Microfluidics; D008875:Middle Aged; D017156:Photoplethysmography; D019339:Port-Wine Stain / Q000473:pathology / Q000503:physiopathology* / Q000532:radiotherapy*; D012039:Regional Blood Flow / Q000528:radiation effects*; D016896:Treatment Outcome; D055815:Young Adult