Real-time three-dimensional velocity vector measurement using the weighted phase gradient method

Although the technique for measuring blood flow based on the ultrasonic Doppler method is an important means for clinical diagnosis, it is inappropriate for quantitative assessment of blood flow since the true three-dimensional (3-D) velocity component cannot be obtained in many cases. In this paper, to overcome the restriction, a new method of 3-D velocity vector measurement is proposed. By detecting the gradient of the weighted phase shift distribution on the receiving aperture, the proposed method enables us to employ a smaller single aperture compared with those used in conventional techniques, and its sensitivity is independent of the direction of transverse flow. Furthermore, real-time measurement can be realized since the autocorrelation technique is utilized for the phase shift extraction as well as the present Doppler method. The basic performance of the method is evaluated by computer simulation. Moreover, sector scan imaging is constructed by the proposed method and compared with the conventional method. The obtained results validated the feasibility and ability of the proposed method for measuring 3-D velocity.