1. A method for locating blood flow in a region of interest using a Doppler ultrasound system having a multi-element transducer, the method comprising: steering an ultrasound beam to deliver ultrasound to and receive echo signals from a plurality of sample locations spatially arranged across the region of interest in two lateral dimensions relative to a reference beam axis extending from the multi-element transducer; for each sample location, processing the echo signals to extract Doppler shift signals and generate Doppler shift data therefrom and accumulating the Doppler shift data for the plurality of sample locations; determining from the Doppler shift data accumulated for the plurality of sample locations the presence of blood flow in the region of interest; and identifying the location in the region of interest at which the presence of blood flow is detected.