The method of the invention controls an ultrasound system that implements a clutter filter, to derive parameters such as blood flow velocity, echo power and/or echo amplitude data from an anatomical region of interest (ROI) and into which a contrast agent has been introduced. The method initially transmits an ensemble of N ultrasound beams along a common azimuth and elevation into the ROI to cause destruction of the contrast agent lying along the azimuth. Estimated wall motion velocity data is then derived for the tissue wall region through use of selected echo signal data derived from a subset of the N ultrasound beams of the ensemble, the subset excluding echo signal data from a first M of the N ultrasound beams or any subset of the N ultrasound beams. The clutter filter is then adjusted to attenuate selected echo signal data returned from the ROI that exhibits the wall motion velocity data. The wall motion data derived from the N ultrasound beams or a subset thereof is processed by the adjusted clutter filter to derive echo data that is better indicative of echo signal returns from the contrast agent or blood flow and is less indicative of wall motion effects.