Modeling shear waves through a viscoelastic medium induced by acoustic radiation force

Area of Science:

• Biomedical Engineering
• Computational Mechanics
• Medical Imaging Physics

Background:

• Accurate simulation of shear wave propagation is crucial for ultrasound-based elastography.
• Tissue phantoms are essential for validating computational models in biomechanical studies.
• Acoustic radiation force (ARF) is a key mechanism for generating shear waves in soft tissues.

Purpose of the Study:

• To develop and validate a finite element model for simulating shear wave generation and propagation in heterogeneous media.
• To compare the efficacy of different acoustic radiation force (ARF) models in simulating experimental observations.
• To identify ARF modeling strategies that balance accuracy and computational efficiency.

Main Methods:

• A finite element model of a viscoelastic phantom with a stiffer inclusion was created.
• Six distinct ARF models were implemented: full push, focal push, point source, and thresholded full push.
• Simulated displacements were compared against experimental data for shear wave speed, attenuation, and displacement recovery.

Main Results:

• The full radiation push model closely replicated experimental shear wave speed and attenuation.
• Peak displacement recovery in simulations did not fully match experimental data for the full push model.
• Focal region or point source ARF models inadequately represented the full push effects.
• Thresholding the full push ARF model yielded comparable results to the full push while reducing computation.

Conclusions:

• Thresholding the full radiation push is a viable method for accurate and efficient ARF simulation in heterogeneous media.
• Focal or point source ARF models are insufficient for accurately capturing shear wave dynamics in this context.
• Finite element modeling, validated with experimental data, provides valuable insights into shear wave propagation for medical imaging applications.