Estimating shear wave speeds and shear viscosities with a viscoelastic time-domain method

Area of Science:

• Medical Imaging
• Biophysics
• Acoustics

Background:

• Shear wave elastography (SWE) uses acoustic radiation force to generate shear waves for speed estimation.
• Current time-domain methods (e.g., cross-correlation) neglect shear viscosity, leading to inaccurate speed measurements due to dispersion.
• Dispersion effects from shear viscosity can significantly impact the reliability of SWE findings.

Purpose of the Study:

• To introduce a novel viscoelastic method for estimating shear wave parameters in the time-domain.
• To address the limitations of existing time-domain methods in SWE by incorporating shear viscosity.
• To evaluate the performance and applicability of the new viscoelastic method.

Main Methods:

• Developed a new viscoelastic time-domain method for shear wave parameter estimation.
• Applied the method to shear wave particle velocity waveforms.
• Validated the method using a simulated three-dimensional viscoelastic Green's function model for shear waves.

Main Results:

• The new viscoelastic time-domain method accurately estimates shear wave speed and viscosity.
• The method is effective outside the push beam region and across a 2D plane.
• Estimates of shear wave speed were comparable or improved compared to cross-correlation methods.

Conclusions:

• The proposed viscoelastic time-domain method enhances the accuracy of shear wave speed estimation in elastography.
• This method overcomes the limitations of dispersion effects caused by shear viscosity.
• The technique provides simultaneous estimation of shear wave speed and viscosity in the time-domain.