Estimation of shear viscosity in a viscoelastic medium with a simplified time-domain model

Shear wave elasticity imaging (SWEI) uses an acoustic radiation force to generate shear waves using conventional ultrasound array transducers, and then mechanical properties of soft tissue are obtained through analysis of shear wave data. SWEI is generally performed using time-of-flight methods that use cross-correlation and time-to-peak methods to obtain estimates of shear wave speed or shear modulus without estimating the shear viscosity. Shear viscosity is responsible for rapid attenuation and dispersion of shear waves, and neglecting the shear viscosity leads to errors in estimated shear wave speeds. To estimate the shear viscosity, a simplified time-domain model is applied to three-dimensional simulated shear particle displacement waveforms. The results show that this approach yields approximate values for the shear viscosity in simulated viscoelastic media at the focal depth and in a 2D plane.