4D Vector Doppler Imaging using Row-Column Addressed Array.

Large aperture 4-dimentional (4D) blood flow Doppler imaging with high temporal resolution remains an important challenge. Different from the conventional matrix array strategy, we proposed a 4D ultrasound vector Doppler (4D-UVD) imaging method using a 128 + 128 row-column addressed (RCA) array and a 256-channel ultrasound platform. This method integrates ultrafast 2D plane waves transmission sequence and least-square multi-angle Doppler velocity estimator. The accuracy of the proposed method was evaluated in both simulations and phantom experiments of parabolic flow. Simulated result shows that the root-mean-squared error (RMSE) of estimated velocity is less than 15%. In the phantom experiments, the relative mean bias B and standard deviation (SD) σ of the velocity profiles are less than 7.9% and 6.9%, respectively, suggesting a high estimated precision. Furthermore, in vivo feasibility of the approach was demonstrated in the human carotid artery. The blood flow velocity of the carotid artery was continuously measured over 7 cardiac cycles at 1 kHz volume-rate. The fluctuations of the estimated mean and peak velocities were highly consistent with the pulse waves measured using a gating pulse sensor, yielding synchronization coefficients of 0.85 and 0.87, respectively. It is thus concluded that the proposed method can achieve a large aperture 4D vector flow imaging with high temporal resolution using RCA probe.