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

OBJECTIVE AND DESIGN: 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. METHODS: Regions of interest 1.8 cm² 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. RESULTS: 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. CONCLUSIONS: 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.