Correlation of laser Doppler wave patterns with underlying microvascular anatomy

Laser Doppler velocimetry (LDV) was performed on the chest, back, and abdomen of four healthy volunteers. As the probe was moved over distances of 2-6 mm, the red-cell flux varied by 100%, but was associated with three distinctive wave patterns. Correlative skin biopsies showed that a high flux, pulsatile pattern superimposed on vasomotor activity was found when the probe was directly over an ascending elastic arteriole with its immediate branches; low flux, pulsatile flow with minimal or no vasomotor activity was found when the probe was off center relative to the ascending arteriole and its branches; and a low flux, non-pulsatile pattern occurred when the probe window was situated between ascending arterioles over an area in the upper horizontal plexus composed primarily of capillaries and post-capillary venules.