Optical coherence tomography detection of shear wave propagation in layered tissue equivalent phantoms

Abstract

In this work, we explored the potential of measuring shear wave propagation using Optical Coherence Elastography (OCE) in a layered phantom and based on a swept-source optical coherence tomography (OCT) system. Shear waves were generated using a piezoelectric transducer transmitting sine-wave bursts of 400 μs, synchronized with an OCT swept source wavelength sweep imaging system. The acoustic radiation force was applied to layered phantoms. The phantoms were composed of gelatin and titanium dioxide. Differential OCT phase maps, measured with and without the acoustic radiation force, demonstrate microscopic displacement generated by shear wave propagation in these phantoms of different stiffness. The OCT phase maps are acquired with a swept-source OCT (SS-OCT) system. We present a technique for calculating tissue mechanical properties by propagating shear waves in inhomogeneous tissue equivalent phantoms using the Acoustic Radiation Force (ARF) of an ultrasound transducer, and measuring the shear wave speed and its associated properties in the different layers with OCT phase maps. This method lays the foundation for future studies of mechanical property measurements of heterogeneous tissue structures, with applications in the study of aneurysms and other intravascular pathologies.