Phased array pulse Doppler tomography

A major problem in ultrasound Doppler has been the lack of quantitation of the complete vectorial velocity distribution in a cross-sectional plane. The authors derive general formulae for the magnitude of the velocity and its direction relative to a known coordinate system using velocity components measured from two beam directions. In order to improve the imaging quality, two methods combining more than two conventional color flow images appropriately are developed. One method is based on weighted averaging of vectorial velocity fields computed from pairs of color flow images. The other method employs the least squares approach, attempting to increase the signal-to-noise ratio. Some results of imaging experiments with both artificial objects and clinical data are presented