Cardiac motion estimation using ultrafast ultrasound imaging tested in a finite element model of cardiac mechanics

Abstract

Recent developments in ultrafast ultrasound imaging allow accurate assessment of 3D cardiac deformation in cardiac phases with high deformation rates. This paper investigates the performance of a multiple spherical wave (SW) ultrasound transmission scheme in combination with a motion estimation algorithm for cardiac deformation assessment at high frame rates. Ultrasound element data of a realistically deforming 3D cardiac finite element model were simulated for a phased array transducer, transmitting five SWs (PRF 2500 Hz). After delayand- sum beamforming, coherent compounding of multiple SW transmissions was performed to generate radiofrequency data (frame rate 500 Hz). Axial and lateral displacements were determined using a normalized cross-correlation-based technique. Good agreement was obtained between estimated and ground truth displacements derived from the model over the cardiac cycle. This study indicates that high frame rate displacement estimation using multiple SWs is feasible and serves as an important step towards high frame rate 3D cardiac deformation imaging.