Performance Assessment of Row-Column Transverse Oscillation Tensor Velocity Imaging using Computational Fluid Dynamics Simulation of Carotid Bifurcation Flow

In this work the accuracy of row-column tensor velocity imaging, i.e., 3-D vector flow imaging in 3-D space over time, is quantified on complex, clinically relevant flow. The quantification is achieved by transferring flow simulated using computational fluid dynamics to a Field II simulation environment and this allows for a direct comparison between the actual and estimated velocities. Carotid bifurcation flow simulations were performed with a peak inlet velocity of 80 cm/s, non-rigid vessel walls, and a flow cycle duration of 1.2 s. The flow was simulated from two observation angles and it was acquired using a 3 MHz 62+62 row-column addressed array at a pulse repetition frequency (fprf) of 10 and 20 kHz. The tensor velocities were obtained at a frame rate of 208.3 Hz, at fprf = 10 kHz, and the results from two velocity estimators were compared. The two estimators were the directional transverse oscillation cross-correlation estimator, and a proposed auto-correlation estimator. Linear regression between the actual and estimated velocity components yielded for the cross-correlation estimator an R2 value in the range of 0.89-0.91, 0.46-0.77, and 0.91-0.97 for the x-, y- and z-components, and 0.87-0.89, 0.40-0.83, and 0.91-0.96, when using the auto-correlation estimator. The results demonstrates that a row-column addressed array can with just 62 receive channels measure complex 3-D flow fields at a high volume rate.