Four-dimensional (4D) phase velocity optical coherence elastography in heterogeneous materials and biological tissue

Area of Science:

• Biomedical Optics
• Medical Imaging
• Biophysics

Background:

• Mechanical property variations in soft tissues serve as crucial biomarkers for clinical diagnosis and disease monitoring.
• Optical coherence elastography (OCE) is a developed technique for investigating biological tissue mechanics, typically analyzing time-domain data to estimate shear wave group velocity.

Purpose of the Study:

• To propose and evaluate a novel method, 4D-OCE phase velocity, for assessing mechanical properties of biological tissues.
• To enable local estimation of phase velocity for propagating mechanical waves in a medium across various frequencies (x, y, z, f).

Main Methods:

• Development and application of a four-dimensional optical coherence elastography (4D-OCE) phase velocity technique.
• Acquisition and analysis of data from homogeneous and heterogeneous phantoms, and ex vivo porcine kidney tissue.
• Comparison with conventional 3D-OCE group velocity estimation and numerical simulations of wave propagation.

Main Results:

• The 4D-OCE phase velocity method successfully estimated local phase velocities of mechanical waves in tested samples.
• Demonstrated capability to analyze mechanical properties with respect to frequency, providing additional information beyond group velocity.
• Numerical simulations illustrated wave propagation boundary behaviors.

Conclusions:

• The proposed 4D-OCE phase velocity method offers a significant advancement in OCE.
• This technique provides deeper insights into the spatial variation of mechanical properties in biological tissues as a function of frequency.
• Enhanced understanding of tissue mechanics can improve diagnostic and monitoring capabilities.