Comparison of SWEI methods for measuring the frequency dependent phase velocity and attenuation in viscoelastic materials
This study compares three analysis methods to determine the frequency dependent phase velocity c(ω) and attenuation α(ω) from shear wave propagation in viscoelastic materials following acoustic radiation force impulse excitations. The analysis methods considered include shear wave spectroscopy, finite window 2D Fourier transform analysis, and analysis using group shear wave speeds (gSWS) calculated using fractional derivatives of the shear wave signals. For simulated shear wave data, results are compared to the true values of c(ω) and α(ω) calculated from the material parameters used in the simulations and show good agreement among the analysis methods, with somewhat lower agreement from the gSWS method in cases with low viscosity. Results from phantom measurements show good agreement among the three methods for measurements of c(ω). For α(ω), there is more scatter among repeated experimental measurements and less agreement among the analysis methods.
