Velocity Profile Reconstruction Using Ultrafast Spectral Analysis of Doppler Ultrasound

Abstmct-An ultrasound pulse Doppler system is discussed, capable of performing real time spectral analysis of data originating from a number of sample volumes. The use of a surface-acoustic-wave-based ultrafast spectrum analyzer allows for a large amount of Doppler data to be processed in a time equal to a few tens of microseconds for each equivalent channel. Sonograms comparable to those obtained in single gate-fast Fourier transform-based-Doppler systems can thus be simultaneously presented, showing the velocity distribution in different sample volumes as a function of time. Alternately, the instantaneous velocity profile can be mapped as a function of depth, thus allowing for the possibility of bidimensional imaging. A prototype flowmeter capable of processing Doppler data from 32 range cells in real time is described and preliminary results obtained in virro under simulated flow conditions are presented.