High Frame Rate Synthetic Aperture 3D Vector Flow Imaging

3-D blood flow quantification with high spatial and temporal resolution would strongly benefit clinical research on cardiovascular pathologies. Ultrasonic velocity techniques are known for their ability to measure blood flow with high precision at high spatial and temporal resolution. However, current volumetric ultrasonic flow methods are limited to one velocity component or restricted to a reduced field of view (FOV), e.g. fixed imaging planes, in exchange for higher temporal resolutions. To solve these problems, a previously proposed accurate 2-D high frame rate vector flow imaging (VFI) technique is extended to estimate the 3-D velocity components inside a volume at high temporal resolutions (< 1 ms). The full 3-D vector velocities are obtained from beamformed volumetric data using synthetic aperture (SA) techniques combined with a 2-D matrix array. The method is validated using Field II simulations of flow along a straight vessel phantom and with complex flow from a 3-D computational fluid dynamics (CFD) model of a carotid bifurcation. Results from the simulations show that the 3-D velocity components are estimated with a mean relative bias of -12.8%, -10% and 1.42% for the Vx, Vy and Vz respectively; each presented a mean relative standard deviation of 11.8%, 12.3% and 1.11%.