On the use of dual acoustic radiation forces to induce shear wave propagation and interference pattern formation

An elasticity imaging system that uses a pair of acoustic radiation forces was developed to generate shear wave interference patterns. Ultrasound pulse-echo data and correlation-based techniques were used to estimate material deformation and to characterize the viscoelastic response. Both normal and axicon focal configurations were implemented and studied to assess impact on shear wave generation. Theoretical models were shown in simulation to describe shear wave propagation and interference pattern properties. In a tissue-mimicking phantom, experimental results were in agreement with theoretical findings. Experimental results also confirm that shear wave interference patterns can be remotely produced in tissue-mimicking material using dynamic acoustic radiation force excitation. Overall, preliminary results are encouraging and the tissue elasticity imaging system described may prove feasible for viscoelastic property characterization in tissue.