title: Use of erythema index imaging for systematic analysis of port wine stain skin response to laser therapy.
abstract: OBJECTIVE
  Quantitative methods to assess port wine stain (PWS) skin response to laser therapy are needed to improve therapeutic outcome. In this study, PWS skin erythema was analyzed using erythema index difference (DeltaEI: erythema index difference between PWS and normal skin) images before and after treatment to investigate systematically subject-dependent response to laser therapy.
  
  
  METHODS
  Cross-polarized digital skin color images were acquired from 17 subjects with facial PWS and the associated DeltaEI images were computed. Qualitative and quantitative analyses of PWS skin erythema were performed with DeltaEI images, in which ranges of 40-6 and 5-0 represented PWS and normal skin, respectively.
  
  
  RESULTS
  After laser therapy, we qualitatively observed a reduction in the DeltaEI values for all subjects. Regression fitting of DeltaEI values before and after PWS laser therapy was associated with strong positive linear correlation.
  
  
  CONCLUSIONS
  The imaging modality and analysis method allowed systematic analysis of PWS skin erythema in response to laser therapy. PWS skin response was dependent on pretreatment DeltaEI values, suggesting that erythema can be utilized as an effective parameter to monitor PWS response to laser therapy.
authors.affiliation: Beckman Laser Institute, University of California, Irvine, CA, USA. bjung@dragon.yonsei.ac.kr
authors.forename: Byungjo
authors.initials: B
authors.lastname: Jung
authors.forename: Chang-Seok
authors.initials: CS
authors.lastname: Kim
authors.forename: Bernard
authors.initials: B
authors.lastname: Choi
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Kelly
authors.forename: J Stuart
authors.initials: JS
authors.lastname: Nelson
mesh_terms: D004890:Erythema / Q000175:diagnosis* / Q000209:etiology; D005145:Face; D006801:Humans; D028022:Low-Level Light Therapy; D010781:Photography; D019339:Port-Wine Stain / Q000150:complications / Q000628:therapy*; D012720:Severity of Illness Index