Estimation of blood velocity vectors using two generalized beam signals

Abstract

Traditional Doppler methods measure only the velocity component along the ultrasound beam direction, and a flow transverse to the beam is not displayed. The lack of information on the beam-flow angle creates an ambiguity that can lead to large errors in velocity magnitude estimates. Different triangle techniques have been proposed, which basically perform multiple measurements of the Doppler frequency shift originating from the same region. In this work, a generalized model is introduced for triangle and non-triangle techniques, in which two ultrasound beams with known relative orientation are directed toward the same vessel. The velocity vector can then be obtained under the condition, when the phase variations of the two beams are linear independence as the functions of the scatter's movement direction. A novel vector estimator is proposed under the framework of the model. It uses only real received signals and their Hilbert transformation and is simulated by Field II, showing suitable for implementatio...