Multi-Frequency Reverberant Shear Waves for Assessing Tissue Dispersion in Optical Coherence Elastography

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Biophysics

Background:

• Optical coherence elastography (OCE) assesses tissue elasticity and viscoelasticity non-invasively.
• Accurate viscoelastic characterization requires multi-frequency shear wave speed (SWS) estimation due to dispersion.
• Frequency-dependent SWS variations impact diagnostic accuracy.

Purpose of the Study:

• Introduce a novel multi-frequency reverberant OCE (MFR-OCE) approach.
• Enhance viscoelastic tissue characterization by capturing shear wave dynamics over multiple frequencies.
• Validate MFR-OCE through simulations and experiments on phantoms and biological tissues.

Main Methods:

• Developed and presented the theoretical framework for MFR-OCE.
• Designed and implemented the experimental setup for MFR-OCE.
• Validated MFR-OCE using simulations, gelatin phantoms, ex vivo porcine cornea, and ex vivo bovine liver.

Main Results:

• MFR-OCE estimated SWS with <4% error in simulations and <3% difference compared to single-frequency OCE in phantoms.
• Frequency-dependent dispersion coefficients from MFR-OCE aligned with the viscoelastic power law model.
• Quantified viscoelastic behavior of phantoms (exponent 0.13), cornea (0.33), and liver (0.51).

Conclusions:

• MFR-OCE enables comprehensive assessment of tissue mechanics.
• The technique accurately captures frequency-dependent shear wave speed variations.
• MFR-OCE holds significant potential for improving diagnostic accuracy in clinical applications.