In Vitro High Resolution Ultrasonography Measurements of Arterial Bifurcations with and without Stenosis as Inputs for In-Silico CFD Simulations

Abstract

Quantification of fluid-structure interactions in arterial walls requires to achieve a complete characterization of flow, shear stress in the interface between blood and endothelium, wall elasticity and wall stresses distribution. Diameter change vs. intravascular pressure is the basis to estimate biomechanical properties (e.g. elasticity, viscosity) of arterial walls in-vivo or in-vitro, being sonomicrometry the gold standard for vessel diameter measurement. High resolution ultrasonography (HRU) is used here in-vitro (as an alternative to sonomicrometry) to get an adequate estimation of the diameter without disturbing the vessel dynamics.

Some experimental in-vitro results are shown for a physical model of arterial bifurcation surgically implemented from a sample of fresh porcine aorta, with and without asymmetric stenosis. Near-physiologic pulsated flow conditions were reproduced in-vitro using a specially designed hemodynamic work bench simulator (HWBS).

In-silico results obtained from a simple CFD model of the abovementioned bifurcation are presented.

Boundary conditions were applied from in-vitro HWBS experimental measurements. Levels of stenosis were reproduced in-silico.

Properly tuned digital simulation based on in-vitro experimental data using our HWBS allows the determination of physical magnitudes (like shear stress) that can’t be obtained easily in experimental in-vitro measurements.