Blood flow CFD simulation on a cerebral artery of a stroke patient

Abstract

The purpose of this paper is to conduct a numerical simulation of the stroke patient's cerebral arteries and investigate the flow parameters due to the presence of stenosis. The computational fluid dynamics (CFD) simulations are based on simplified and realistic cerebral artery models. The seven simplified models (benchmarks) include straight cylindrical vessels with idealized stenosis with variable d/D (0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1). The realistic model of the cerebral artery is based on magnetic resonance imaging (MRI) for patient-specific cerebral arteries. The simulation for the realistic model of the cerebral artery is performed at boundary conditions measured by ultrasonography of the input and the output flow profiles (velocity and pressure). The obtained CFD results of the benchmarks are validated with actual data from the literature. Furthermore, a previous vascular contraction is assumed to be exist and the effect of this contraction area ratio on the blood flow regime is discussed and highlighted. Furthermore, CFD results show that a certain vascular contraction area critically affects the blood flow which shows increasing the wall shear stress WSS at the stenosis site. An increase in the blood velocity and vortex appears after the contraction zone, this lead to vessel occlusion and strokes. Article highlights The pressure drop across the arterial contraction is reduced when the area ratio d/D is increased. In some cases, the vortex can prevent blood flow from crossing, this leads to vessel occlusion especially at low d/D The WSS near the contraction area is high. Increasing the WSS can cause embolism that leads to lead to vessel occlusion.

Coronary hemodynamic simulation study

“…Fluid Domain: Set 1 pressure inlet (INLET) and 2 pressure outlets (OUTLET) to simulate the physiological conditions in the actual biological vascular system. 14 The fluid-solid interface is set as the system coupling interface, and the fluid-solid two-way coupling is carried out in the form of a moving mesh.…”

The Physics of Stroke

“…To worsen the matter, because of red cell activation brought about by the abnormal flow pattern at such narrowed points, there could be thrombus formation that could completely occlude the narrowed point to cause full cerebral infarction beyond the point given the turbulence. 9…”

“…These cause white matter hyperintensities and lacunar infarcts which make stroke outcome worse. 9 For stroke, a lot has to do with intracranial vascular disease. When flow is undisturbed, the brain cells get adequate amounts of oxygen and nutrients, hence functioning optimally.…”

“…To worsen the matter, because of red cell activation brought about by the abnormal flow pattern at such narrowed points, there could be thrombus formation that could completely occlude the narrowed point to cause full cerebral infarction beyond the point given the turbulence. 9 At points of bifurcation, laminar flow which is characterized by concentric layers of blood moving in parallel changes to turbulent flow. With the former the highest velocity is found in the center of the vessel and the lowest along the vessel wall; ensuring low shear stress and low potential for endothelial dysfunction.…”

Hemodynamic and fluid flow analysis of a cerebral aneurysm: a CFD simulation

“…Hemodynamic analysis of the vascular systems of the patients introduced a significant value to understand and diagnose its diseases [1,2] such as stenosis [3], aneurysms [4] (such as fusiform [5], saccular, false and dissection types [6]), and angiosclerosis. The computational fluid dynamics (CFD) simulations for the hemodynamic analysis are used to investigate various parameters such as the flow structure, recirculation flow, wall pressure, and wall shear stress (WSS) [7][8][9].…”