Broadband-excitation-based mechanical spectroscopy of highly viscous tissue-mimicking phantoms

TL;DR

This paper introduces a novel optical method for broadband mechanical spectroscopy of viscous tissue-mimicking phantoms, enabling high-frequency analysis of local tissue dynamics beyond standard rheometer limits.

Contribution

It presents a new 2D Fourier analysis technique for broadband Rayleigh wave propagation, validated against traditional methods, to assess local viscoelastic properties at high frequencies.

Findings

Validated method against monochromatic and oscillatory tests

Enables high-frequency local tissue property assessment

Potential applications in disease-related tissue microstructure analysis

Abstract

Standard rheometers assess mechanical properties of viscoelastic samples up to 100~Hz, which often hinders the assessment of the local-scale dynamics. We demonstrate that high-frequency analysis can be achieved by inducing broadband Rayleigh waves and monitoring their media-dependent propagation using Optical Coherence Tomography. Here, we present a new broadband wave analysis based on two-dimensional Fourier Transformation. We validated this method by comparing the mechanical parameters to monochromatic excitation data and a standard oscillatory test. Our method allows for high-frequency mechanical spectroscopy, which could be used to investigate the local-scale dynamics of different biological tissues and the influence of diseases on their microstructure.