Direct comparison of laser Doppler flowmetry and laser Doppler imaging for assessment of experimentally-induced inflammation in human skin

Laser Doppler imaging (LDI) and laser Doppler flowmetry (LDF) can measure localized skin perfusion. The purpose of the study was to directly compare LDF with LDI as a tool for measuring skin blood changes in an experimental model of chemically-induced skin inflammation. Regions of interest 1.8 cm(2) in area on the forearm skin of eight healthy volunteers were randomized and exposed to 0.25, 0.5, 1, or 2 % topical sodium lauryl sulfate (SLS) or vehicle for 24 h. Mean blood flow was measured by LDI and LDF at 24, 48, and 72 h. Inflammation was clinically graded using a standardized, clinical score. Sodium lauryl sulfate induced significant, dose-dependent local inflammation. Both Doppler methods were significantly correlated with the clinical grading (LDF, r = 0.755; LDI, r = 0.836). LDF and LDI showed similar significance differences with regard to dose- and time-response patterns compared to the vehicle. The absolute and relative LDF and LDI values were significantly correlated. Laser Doppler flowmetry and LDI showed similar dose- and time-response relations in irritant-induced inflammatory skin reactions. For the assessment of localized skin reactions, LDI possesses no apparent advantages over the less expensive LDF method for grading dermal inflammatory reactions.