Modeling and computation of propagating waves from coronary stenoses

Abstract

The ability to reliably detect coronary artery disease based on the acoustic noises produced by a stenosis can provide a simple, non-invasive technique. Current research exploits the shear wave fields in body tissue to detect and analyze coronary stenosis. A mathematical model of this system couples the generation of these acoustic noises with the propagation of the sound and shear waves through the chest cavity. In our initial investigations we consider a one-dimensional homogeneous viscoelastic model. A quasi-linear viscoelastic stress-strain relationship was proposed by Eung for a variety of biological tissues. Though an effective model, this formulation presents significant computational difficulties in dynamic situations. We present several alternate constitutive relations based on an internal variable formulation that approximate Fung's constitutive relation well when optimized. More importantly, results from the corresponding dynamic models match well with simulated data of wave propagation through a homogeneous soft tissue-like gel.