Pulsed Doppler ultrasound system for the measurement of velocity distributions and flow disturbances in arterial prostheses.

For the investigation of flow through prosthetic arteries a pulsed Doppler ultrasound system has been characterized. Preliminary in vitro experiments using this system are described; they verify its suitability for making velocity profile and flow disturbance measurements. The output from a frequency tracker is compared with spectral analysis of Doppler signals for both laminar and turbulent flow regimes and the root mean square fluctuations on the tracker output signal are used to identify transition from laminar to turbulent flow. In addition, the turbulent intensity of poststenotic flow is quantified at several axial locations and for different rates of flow. Finally, we present velocity profile measurements which were obtained using a deconvolution technique to account for the finite size of the sample volume.