SPATIAL AND TEMPORAL EVALUATION OF LOCALLY INDUCED SKIN TRAUMA RECORDED WITH LASER-DOPPLER TECHNIQUES

The single-fiber laser Doppler flowmetry (SF-LDF) technique has been u sed to study perfusion within tissues. The insertion of the SF-LDF pro be into human skin locally alters microcirculation for more than 70 mi n after positioning. In this study the SF-LDF and a newly developed la ser Doppler imager (LDI) were used to describe the spatial distributio n, the intensity, and the temporal course of the trauma following intr acutaneous insertion of the probe. The LDI scanned a human skin area o f 6 x 6 cm (36 x 36 pixels). A flexible SF-LDF probe was inserted intr adermally in the same measuring region. Recordings were performed for 120 min with the two techniques simultaneously. With the SF-LDF probe maximal hyperemia was recorded after 5-30 min. After a gradual and slo w decrease most of the subjects reached a steady-state level within 80 -100 min. A 3-min tourniquet occlusion test was performed 120 min afte r SF probe positioning. A significant hyperemic response was recorded, indicating that almost no posttraumatic activity was present at this time. The area of increased perfusion recorded with the LDI had an ova l to circular configuration with a maximal extension after 5-10 min (r adius 1.5-2 cm, area 8.9 cm(2)). The zone of maximal hyperemia was dis tributed adjacent to the intradermal probe, gradually decreasing towar d the periphery. No significant hyperemia was shown with LDI after 100 min. There was a concordance between the time courses of the hyperemi c response obtained with the two techniques. (C) 1996 Academic Press, Inc.