Assessing the viscoelasticity of chicken liver by OCE and a Rayleigh wave model

Abstract

This study investigates the feasibility of quantifying the viscoelasticity of soft tissues with a dynamic noncontact optical coherence elastography (OCE) technique coupled with a Rayleigh wave model. Spectral analysis of an air-pulse induced elastic wave as measured by OCE provided the elastic wave dispersion curve. The dispersion curve was fitted to an analytical solution of the Rayleigh wave model to determine the Young’s modulus and shear viscosity of samples. In order to validate the method, 10% gelatin phantoms with and without different concentrations of oil were prepared and tested by OCE and mechanical testing. Results demonstrated that the elasticities as assessed by the Rayleigh wave model generally agreed well with mechanical testing, and that the viscosity in the phantom with oil samples was higher than the phantoms without oil, which is in agreement with the literature. Further, this method was applied to quantify the viscoelasticity of chicken liver. The Young’s modulus was E=2.04±0.88 kPa and the shear viscosity was η=1.20±0.13 Pa·s with R2=0.96±0.04 between the OCE-measured dispersion curve and Rayleigh wave model analytical solution. Combining OCE and the Rayleigh wave model shows promise as an effective tool for noninvasively quantifying the viscoelasticity of soft tissues.