Pulse-Wave Propagation in Straight-Geometry Vessels for Stiffness Estimation: Theory Simulations Phantoms and In Vitro Findings

摘要

Pulse wave imaging (PWI) is an ultrasound-based method for noninvasive characterization of arterial stiffness based on pulse wave propagation. Reliable numerical models of pulse wave propagation in normal and pathological aortas could serve as powerful tools for local pulse wave analysis and a guideline for PWI measurements in vivo. The objectives of this paper are to (1) apply a fluid-structure interaction (FSI) simulation of a straight-geometry aorta to confirm the Moens-Korteweg relationship between the pulse wave velocity (PWV) and the wall modulus, and (2) validate the simulation findings against phantom and in vitro results. PWI estimates the pulsatile wall displacement along the abdominal regions of canine aorta in vitro in sequential RF ultrasound frames and estimates the PWV in the imaged wall. The same system was also used to image the performance of similar estimations in polyacrylamide phantoms, mimicking the canine measurements as well as modeling softer and stiffer walls. Finally, the model parameters from the canine and phantom studies were used to perform 3D two-way coupled FSI simulations of pulse wave propagation and estimate the PWV. The simulation results were found to correlate well with the corresponding Moens-Korteweg equation. A high linear correlation was also established between PWV² and E data across the combined simulation and experimental findings combined (R²= 0.98) confirming the relationship established by the aforementioned equation.