Multi-acquisition multi-resolution full-waveform shear wave elastography for reconstructing tissue viscoelasticity.

Area of Science:

• Medical Imaging
• Biophysics
• Ultrasound Technology

Background:

• Tissue elasticity is crucial for diagnostics, but viscosity offers additional value.
• Current shear wave elastography (SWE) primarily focuses on elasticity, often limited to 2D.
• Reconstructing 3D viscoelastic properties is a significant challenge in medical imaging.

Purpose of the Study:

• To develop robust methodologies for reconstructing combined elasticity and viscosity maps of soft tissues beyond the measurement plane using SWE.
• To enable 3D viscoelasticity imaging from conventional ultrasound scanners.
• To explore novel biomarkers for enhanced diagnostic specificity.

Main Methods:

• A novel combination of multiresolution imaging, multi-plane SWE data acquisition, and sequential reconstruction.
• Utilizing lower frequency data for initial low-resolution maps, refined with higher frequencies.
• Simultaneous inversion of data from multiple planes and pushes, followed by sequential elasticity and viscosity map reconstruction.

Main Results:

• Successfully reconstructed viscoelastic properties of synthetic homogeneous and heterogeneous inclusions.
• Demonstrated feasibility with shear modulus from 3 to 20 kPa and viscosity from 1 to 3 Pa·s.
• Elasticity imaging was robust even at low signal-to-noise ratios (SNR), while viscosity imaging required higher SNR.

Conclusions:

• The proposed methodology offers a feasible approach to 3D viscoelasticity reconstruction using conventional ultrasound.
• This technique has the potential to generate more specific diagnostic biomarkers than current 2D elasticity imaging.
• Further research is needed to optimize viscosity imaging, especially in low SNR conditions.