Power spectral density function of ultrasound Doppler in the microcirculation

For many capillary orientation models, the maximum expected spectral power is at the maximum Doppler shift. Additionally, by gating the signal to measure blood flow only during diastole, many of the pulse and pulse-related movement artifacts are minimized or deleted from the signal. Our results indicate the presence of blood flow related signals that result from the small arteries or capillaries at the finger tip.