1. A method for measuring pressure gradient with ultrasound, the method comprising: scanning multiple spatial locations with an ultrasound system, the spatial locations being fluid locations; automatically computing, with the ultrasound system in real time with the scanning, pressure gradients as a function of ultrasound data responsive to the scanning of the multiple spatial locations; wherein scanning comprises scanning a two or three dimensional region with ultrasound for velocity information, and wherein automatically computing as a function of the ultrasound data comprises computing the pressure gradients, for spatial locations distributed in two or three dimensions, as a function of velocity data representing the two or three dimensional region at a given time; displaying an image of pressure gradients distributed over all the two or three dimensions within the two or three dimensional region; applying an anti-aliasing filter for each depth as a function of time to the ultrasound data; and applying a spatial-temporal filter to the ultrasound data.