Vector flow imaging (VFI) improves the operator's workflow allowing the quantitative evaluation of blood flow with no need for manual angle corrections. Currently, commercial VFI implementations are based on a line-by-line estimation, compromising the frame rate and the possibility of imaging fast flow dynamics. High-frame-rate methods are, however, computationally demanding. The objective of this work is to demonstrate that quantitative VFI can be achieved in-vivo at high-frame-rate using only six pre-beamformed lines and with lowered requirements for the ultrasound system.