Simulation of RF data with tissue motion for optimizing stationary echo canceling filters

Blood velocity estimation is complicated by the strong echoes received from tissue surrounding the vessel under investigation. Proper blood velocity estimation necessitates use of a filter for separation of the different signal components. Development of these filters and new estimators requires RF-data, where the tissue component is known. In vivo RF-data does not have this property. Instead simulated data incorporating all relevant features of the measurement situation can be employed. One feature is the motion in the surrounding tissue induced by pulsation, heartbeat, and breathing. This study has developed models for the motions and incorporated them into the RF simulation program Field II, thereby obtaining realistic simulated data. A powerful tool for evaluation of different filters and estimators is then available. The model parameters can be varied according to the physical situation with respect to scan-site and the individual to be scanned. The nature of pulsation is discussed, and a relation between the pressure in the carotid artery and the experienced vessel wall motion is derived.