An ultrasonic diagnostic imaging for analyzing shear wave characteristics utilizes a background motion compensation subsystem which acts as a spatial filter of pulse-to-pulse autocorrelation phases over the ROI of tracking pulse vectors to compensate for background motion. The subsystem is configured to compute the sum of all lag-1 autocorrelations of tracking line ensemble data over the tracking ROI, for each PRI. The inventive technique does not significantly reduce sensitivity to shear waves, because the shear wave is spatially smaller than the ROI.