Improved two-point frequency shift power method for measurement of shear wave attenuation

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Acoustics

Background:

• Quantitative assessment of biological soft tissue mechanical properties is crucial for diagnosis.
• Ultrasound shear wave elastography (SWE) is a noninvasive modality for evaluating tissue viscoelasticity.
• Current SWE methods often rely on phase velocity curves or various shear wave attenuation techniques.

Purpose of the Study:

• To introduce and validate an improved method for measuring shear wave attenuation in viscoelastic tissues.
• To present the two-point frequency shift power (2P-FSP) method, an advancement over the two-point frequency shift (2P-FS) technique.
• To assess the influence of measurement location and distance on the 2P-FSP method's performance.

Main Methods:

• Developed the data-driven 2P-FSP method, which analyzes power spectra frequency shifts of shear waves at two positions.
• Tested the 2P-FSP method using numerical simulations in tissue-mimicking viscoelastic media.
• Validated the method with experimental data from custom phantoms and ex vivo porcine liver samples.

Main Results:

• The 2P-FSP method demonstrated robustness to noise, outperforming the 2P-FS technique at lower signal-to-noise ratios (SNR).
• Performance improvements were observed for measurements taken farther from the initial acoustic radiation force (ARF) push location.
• The study confirmed the method's applicability for measuring shear wave attenuation in viscoelastic soft tissues.

Conclusions:

• The 2P-FSP method offers a reliable and improved approach for quantifying shear wave attenuation in soft tissues.
• This data-driven technique eliminates the need for rheological models, simplifying analysis.
• 2P-FSP enhances the capabilities of ultrasound shear wave elastography for mechanical property assessment.