Development of a Patient-Specific Carotid Artery Fluid-Structure-Interaction Model

Development of a Patient-Specific Carotid Artery Fluid-Structure-Interaction Model

Liu, Yanjing (TU Delft Mechanical, Maritime and Materials Engineering)

Akyildiz, A.C. (mentor)
Tziotziou, A. (graduation committee)

Delft University of Technology

Mechanical Engineering

2023-12-22

Background:
Ischemic stroke is a major cause of death worldwide. Atherosclerosis in the carotid arteries is an established predictor of these events. FSI shows its advantage in simulating the hemodynamic environments due to involving the multiphysics coupling of fluid dynamics and structural mechanics regulations. Therefore, the aim of this thesis was to establish and demonstrate a framework, starting with the segment data extracted from CTA images and leading to patient-specific FSI modeling. Thus the results can be used to gain insights into the relationship between plaque changes over time and biomechanical stresses induced by blood flow using FSI.

Method:
3D coordinates are firstly extracted from CTA scans of patients with calcified atherosclerotic plaques in their carotid arteries, sourced from the PARISK study. This data was then used to reconstruct 3D surfaces and volumes of the carotid bifurcation structure. Subsequently, the Backward Incremental method is employed to compute the initial stresses and establish the zero-pressure geometry of the vessel. Following this, FSI simulations were conducted on six carotid bifurcations to obtain preliminary results, providing an initial test of the pipeline's robustness. Morphological changes, including plaque burden, wall thickness, and calcium distance, are quantified to study plaque progression over time. The numerical simulation results provide insights into biomechanical stresses, including fluid and solid wall shear stress and von Mises stress. The simulation results are subjected to post-processing for further analysis. The results are mapped to a 2D configuration, with 1.5mm along the centerline and 45 degree per sector to study the local behavior.

Result:
The efficacy of the reconstruction and initial stress detection methods shows the robustness of the pipeline. The entire process is executed on six vessels, with a comprehensive examination of one case presented initially. This detailed analysis reveals metrics related to morphological changes, biomechanical stresses, and flow patterns. Subsequently, correlation and stress distribution analyses are conducted for all six vessels. Notably, negative correlations are discerned between stress and morphological changes, adding depth to the understanding of the relationship between biomechanics and morphological changes in these cases.

Atherosclerosis
Fluid-Structure-Interaction
Plaque Progression
Shear Stress
Structural Stress

http://resolver.tudelft.nl/uuid:9335f974-9adb-41f7-b6c2-3b87201913f6

Student theses

master thesis

© 2023 Yanjing Liu