Shear Wave Imaging Framework for Quantification of Myocardial Tissue Properties

Abstract

Analysis of myocardial and arterial wall tissue properties can potentially be used to diagnose cardiovascular pathophysiology. Many cardiovascular diseases, such as Left Bundle Branch Block, Myocardial Infarcts and arteriosclerosis alters tissue elasticity. A known analogue to tissue elasticity is the velocity of the propagating shear waves through tissue, which can be quantified non-invasively as shear wave velocity, derived from ultrasound Shear Wave Imaging (SWI). Developing new SWI techniques require custom programming and a deep knowledge of research-based ultrasound systems. A SWI framework was developed to identify natural shear waves in 800ms windows and generate an acoustic radiation force pulse for generating artificial shear waves in tissue, for use in linear and phased array setups. The MATLAB code and setup framework are provided as an open-source package made available on GitHub.To verify the SWI framework, Acoustic Radiation Force, followed by SWI were made in a tissue mimicking ultrasound phantom. Shear waves propagated at 2.71 ± 0.12 𝑚/𝑠, which did not vary significantly with respect to neither scan depth (P=0.77) nor tissue attenuation (P=0.88). The framework can potentially be useful for aspiring researchers starting their work in SWI imaging using the Verasonics Vantage System.