Parametric imaging of viscoelasticity using optical coherence elastography

Abstract

We demonstrate imaging of soft tissue viscoelasticity using optical coherence elastography. Viscoelastic creep deformation is induced in tissue using step-like compressive loading and the resulting time-varying deformation is measured using phase-sensitive optical coherence tomography. From a series of co-located B-scans, we estimate the local strain rate as a function of time, and parameterize it using a four-parameter Kelvin-Voigt model of viscoelastic creep. The estimated viscoelastic strain and time constant are used to visualize viscoelastic creep in 2D, dual-parameter viscoelastograms. We demonstrate our technique on six silicone tissue-simulating phantoms spanning a range of viscoelastic parameters. As an example in soft tissue, we report viscoelastic contrast between muscle and connective tissue in fresh, ex vivo rat gastrocnemius muscle and mouse abdominal transection. Imaging viscoelastic creep deformation has the potential to provide complementary contrast to existing imaging modalities, and may provide greater insight into disease pathology.

An approach to viscoelastic characterization of dispersive media by inversion of a general wave propagation model

“…14 In optical coherence tomography (OCT), some work has been done for the viscoelastic measurement of tissue assuming a rheological model. [15][16][17][18] Most of them utilize frequency-dependent wave speed measurements to¯t with theoretical models of dispersion (rheological models), disregarding valuable information given by the wave attenuation process. Therefore, the use of model-independent approaches for the viscoelastic characterization of tissue is an important trending topic in elastography since it can provide an accurate intrinsic information without assumptions of the tissue mechanical behavior, which is in many cases unknown.…”

Optical coherence elastography – OCT at work in tissue biomechanics [Invited]

“…), or attempting to exploit the time dependence to extract more information. However, such studies of viscoelasticity in OCE are in their infancy [45,109,110,150]. At the same time, as described in Section 3, soft tissue responds in a nonlinear fashion to stress and the tangent modulus depends on stress, or equivalently, strain.…”

“…Although viscoelasticity has been discussed in Section 6 [150] and Section 7 [45,64,[109][110][111], it is has featured necessarily little in this review, because there is little work explicitly focusing on the viscosity of soft tissue [150], although that is not the case for the wider field of optical elastography [182,199].…”

Magnetomotive Optical Coherence Elastography for Magnetic Hyperthermia Dosimetry Based on Dynamic Tissue Biomechanics

“…3(c)). The τ c metrics, along with a constant strain parameter, have also been demonstrated with static OCE, where a four-parameter Kelvin-Voigt model was utilized and parametric B-scan images of ex vivo rat and mouse muscles were generated [84]. In addition, the creep phenomenon can be explained by applying a harmonic oscillation force F 0 e iwt with angular frequency ω = 2πf to the sample using Eq.…”