An ultrasound imaging system (100) includes a transducer array (102) with plurality of transducer elements (200) configured to transmit an ultrasound signal and receive echoes. Transmit circuitry (104) is configured to excite the transducer elements to transmit the ultrasound signal along a propagation direction. Receive circuitry (106) is configured to receive an echo signal produced in response to the ultrasound signal traversing flowing structure in the field of view. A beamformer (112) is configured to beamform the echo signal and produce a single directional signal at a depth. The directional signal is transverse to the propagation direction of the ultrasound signal. A velocity processor (114) is configured to transform the directional signal to produce a corresponding quadrature signal, estimate a depth velocity component and a transverse velocity component at the depth based on the directional signal and the quadrature signal, and generate a signal indicative of the estimate.