Systems and methods for processing echo signals in a Doppler ultrasound system from a region of interest. An ultrasound beam is electronically steered to deliver ultrasound to and receive echo signals from a plurality of sample locations in the region of interest. The echo signals for each sample location are processed to extract Doppler shift signals and Doppler shift data representing the Doppler shift signals are generated. The Doppler shift data accumulated for the sample locations can be used to detect the presence of blood flow in the region of interest, and identify the location in the region of interest at which the presence of blood flow is detected. The blood flow can be tracked by updating the location of the detected blood flow in the region of interest. The blood flow can be further monitored by combining the locating and tracking functionality with an m-mode ultrasound image.
