Elasticity and viscosity estimation from shear wave velocity and attenuation: A simulation study

Shearwave Dispersion Ultrasound Vibrometry (SDUV) measures tissue elasticity and viscosity by quantifying dispersion of shear wave propagation velocity. Long tone bursts of focused ultrasound are transmitted by an array transducer to a push origin at a pulse repetition frequency of f_p to produce multi-tone shear waves at f_p and its harmonics. Shear waves are monitored by pulse echo ultrasound transmitted by the same array transducer between the push tone bursts. The Voigt dispersion model is fitted to shear wave velocities measured at multiple frequencies to estimate elasticity μ₁ and viscosity μ₂. Alternatively, μ₁ and μ₂ can be calculated from shear wave amplitude attenuation and shear velocity at frequency f_p also based on Voigt model. In the present study, these two approaches were compared using simulation data. Field II was used to simulate ultrasound radiation force field generated by a linear array transducer. Motion in a homogenous viscoelastic medium was calculated using the Green´s function. Simulation results showed comparable estimations for both methods when SNR was high. When SNR was low, the amplitude attenuation method was more robust than the velocity method.