Shear wave elasticity imaging (SWEI) enables the quantitative assessment of the mechanical properties of tissue. In SWEI, the effective generation of acoustic radiation force is of paramount importance. Consequently, several research groups have investigated various transmit beamforming and pulse-sequencing methods. To further improve the efficiency of shear wave generation, and therefore, to increase the quality of SWEI, we introduce a technique referred to as “multi-angle compound SWEI” (MAC-SWEI), which uses simultaneous multi-angular push beams created by dual-phase transmit focusing. By applying a constant phase offset on every other element of an array transducer, dual-phase transmit focusing creates both main and grating lobes (i.e., multi-angular push beams for pushing) to simultaneously generate shear waves with several wave-front angles. The shear waves propagating at different angles are separated by multi-directional filtering in the frequency domain, leading to the reconstruction of multiple spatially co-registered shear-wave velocity maps. To form a single elasticity image, these maps are combined, while regions associated with known artifacts created by the push beams are omitted. Overall, we developed and tested the MAC-SWEI method using Field II quantitativesimulations and the experiments performed using a programmable ultrasoundimaging system. Our results suggest that MAC-SWEI with dual-phase transmitfocusing may improve the quality of elasticity maps.
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