Spatial Assessment of Heterogeneous Tissue Natural Frequency Using Micro-Force Optical Coherence Elastography

Area of Science:

• Biomedical Engineering
• Ophthalmology
• Biophysics

Background:

• Corneal natural frequency analysis is a promising biomarker for corneal biomechanics.
• Optical coherence tomography elastography (OCE) is used for this analysis.
• The ability of OCE to detect local tissue variations is not well understood.

Purpose of the Study:

• To evaluate if natural frequency analysis can resolve local variations in heterogeneous tissue structures.
• To assess the correspondence between natural frequency distributions and regional structural variations.

Main Methods:

• Induced sub-micrometer oscillations in samples using air pulses.
• Detected oscillations point-wise with a 1,300 nm spectral domain common path OCT system.
• Analyzed oscillation features using Fast Fourier Transform and a single degree of freedom model.

Main Results:

• Natural frequency analysis successfully distinguished between silicone and agar, and between different tissues in a beef shank sample.
• Local frequency variations correlated with regional structural differences in heterogeneous samples.
• The method demonstrated sensitivity to global and local structural features.

Conclusions:

• Natural frequency OCE can characterize global and local features of heterogeneous samples.
• This technique offers complementary information to existing corneal biomechanical assessments.
• It holds potential as a clinical tool for ocular disease detection and treatment outcome evaluation.