Multi-Channel Optical Coherence Elastography Using Relative and Absolute Shear-Wave Time of Flight

Area of Science:

• Biophysics
• Cellular Biology
• Biomedical Imaging

Background:

• Elastography is established for macroscopic tissue imaging.
• Scaling down elastography offers potential for cellular biomechanics research.
• Optical coherence tomography (OCT) is a non-invasive imaging modality.

Purpose of the Study:

• To evaluate the feasibility of modifying an optical coherence tomography (OCT) device for cellular elastography.
• To measure shear wave speed in a 3D medium for assessing elastic properties.
• To explore the application of OCT-based elastography in cellular biology research.

Main Methods:

• A commercial swept-source OCT system was modified to detect shear waves.
• Shear waves were generated by vibrating a needle embedded in a gel.
• Shear wave speed was calculated using time-of-arrival differences from OCT M-mode images.

Main Results:

• The relative time-of-arrival method accurately measured shear wave speed in homogeneous gels (R2 = 0.95).
• Precision was limited by the 184-micrometer inter-channel distance.
• The approach demonstrated potential for research in cancer cell biology.

Conclusions:

• Modified OCT can measure shear wave speed for cellular elastography.
• The technique shows promise as a research tool for investigating cell mechanics.
• Further optimization and resolution assessments are needed for 3D elastograms.