1. A method of analyzing movement of blood and/or anatomical structures within a region of interest, operating in conjunction with B-mode and/or color flow imaging modes, the method comprising: activating a transmit aperture within a multi-element transducer array; transmitting one or more ultrasonic beams along one or more scan directions that span the region of interest; for each transmit event, receiving ultrasound echoes from each element of a receive aperture; grouping the receive channel echo data into two or more sets corresponding to different receive sub-apertures; combining each sub-aperture data set to generate partially focused echo-location data for one or more reconstruction lines; and storing all the sub-aperture echo data sets during a storage period in a format that can be retrieved for later analysis.