In-vivo 4D Ultrafast vector flow imaging: Quantitative assessment of arterial blood flow

In this study, we propose 4D Ultrafast vector flow imaging, through the use of 4D plane-wave ultrafast and cross-beam vector Doppler imaging in order to map in-vivo blood flows in 3D, provide volumes of complex vector flow fields at high frame rate, and quantify the volumetric flow rate accurately. 4D Ultrafast vector flow imaging was performed in large volumetric field of views at high volume rates (>4000 volumes/s) using a 1024-channel 4D ultrafast scanner and a 2D matrix-array probe. The accuracy and precision of the technique was evaluated in-vitro in an artery phantom and compared with an industrial flow meter. Volumetric flow rate errors of less than 5% were found when volumetric flow rates were less than 360 ml/min. In-vivo feasibility was evaluated in 2 human carotid arteries. 4-D blood flow velocity was assessed during one heartbeat and in a full volume and volumetric flow rates of 375 ± 57 ml/min and 275 ± 43 ml/min were estimated. Finally, vortices were imaged in 3D at the carotid artery bifurcation.