Multiphysics computational models for cardiac flow and virtual cardiography

Abstract

A multiphysics simulation approach is developed for predicting cardiac flows as well as for conducting virtual echocardiography (ECHO) and phonocardiography (PC) of those flows. Intraventricular blood flow in pathological heart conditions is simulated by solving the three-dimensional incompressible Navier-Stokes equations with an immersed boundary method, and using this computational hemodynamic data, echocardiographic and phonocardiographic signals are synthesized by separate simulations that model the physics of ultrasound wave scattering and flow-induced sound, respectively. For virtual ECHO, a Doppler ultrasound image is reproduced through Lagrangian particle tracking of blood cell particles and application of sound wave scattering theory. For virtual PC, the generation and propagation of blood flow-induced sounds ('hemoacoustics') is directly simulated by a computational acoustics model. The virtual ECHO is applied to reproduce a color M-mode Doppler image for the left ventricle as well as continuous Doppler image for the outflow tract of the left ventricle, which can be verified directly against clinically acquired data. The potential of the virtual PC approach for providing new insights between disease and heart sounds is demonstrated by applying it to modeling systolic murmurs caused by hypertrophic cardiomyopathy.

Modeling Left Ventricular Blood Flow Using Smoothed Particle Hydrodynamics

“…Past studies have shown that by choosing appropriate inlet information together with global geometric and flow parameters that are within physiological range, computational models with simplified valve structures can reproduce the flow features associated with LV function with reasonably accuracy 29, 35, 38, 57, 58 . It is well known that for a computational heart model to become a clinically relevant simulation tool it must be able to capture the FSI between the blood flow and the heart valves 59 .…”

Flow patterns in the jugular veins of pulsatile tinnitus patients

“…Similarly, vortical instabilities and pressure fluctuations induced near the lumen wall have been described as a source of audible sound that can be auscultated at the aortic root (Seo et al, 2013). While arterial stenosis and Seo's work explicitly reference unstable flow, the results presented here are expected to represent stable flow due to the low, steady flow rates imposed.…”

Left Ventricular Fluid Mechanics: The Long Way from Theoretical Models to Clinical Applications

“…In a recent work, starting from the numerical results, virtual Echocardiographic and Phonocardiographic signals were synthetized, showing the feasibility to reproduce in silico the data normally acquired in the clinical practice. 88 …”