Viscosity measurement based on shear-wave laser speckle contrast analysis

Area of Science:

• Biomedical Optics
• Acoustic Elastography
• Biophysics

Background:

• Tissue viscosity is a key indicator of pathological changes and tissue properties.
• Accurate measurement of tissue viscosity is crucial for effective tissue characterization.
• Optical methods offer potential for non-invasive tissue assessment.

Purpose of the Study:

• To develop and validate an optical method for measuring continuous shear-wave propagation in optically turbid media.
• To quantitatively estimate tissue viscosity using shear-wave attenuation coefficients.
• To assess the accuracy and consistency of the developed optical technique.

Main Methods:

• Utilized shear-wave laser speckle contrast analysis (SW-LASCA) to track shear-wave propagation.
• Generated shear waves in tissue-mimicking phantoms using amplitude-modulated ultrasound (100-600 Hz).
• Calculated shear-wave attenuation coefficients and estimated viscosity using the Voigt model.

Main Results:

• Successfully tracked shear-wave propagation at centimeter depths in turbid phantoms.
• Measured shear-wave attenuation coefficients across a range of frequencies (100-600 Hz).
• Derived viscosity values showed a maximum standard deviation of 9%, consistent with prior non-optical measurements.

Conclusions:

• The developed optical method (SW-LASCA) provides a reliable means to estimate tissue viscosity.
• This technique enables quantitative tissue characterization in optically turbid environments.
• The findings support the use of optical methods for assessing tissue mechanical properties.