Investigating Stalling Events in Cerebral Blood Microcirculation and Implications for Cognitive Disease

The present doctoral thesis explores the sophisticated dynamics of cerebral blood flow and the related blood distribution factors in the context of brain microcirculation considering various physiological and pathological conditions applied in the brain microvasculature. The study focuses on the impact of the stalling events in the aged brain on blood pressure, hematocrit levels, transit time, and occlusions while considering the uneven distribution of the blood components at the bifurcation on the microcirculation structure. Additionally, the thesis aims to analyze the effects of the non-Newtonian viscosity on cerebral blood flow and apply the directed graph theory to reduce the computational cost of the mathematical model and make it plausible to use the computational fluid dynamics methods on the complex, realistic, dense, tortuous microvascular in the brain. The research employs advanced path analysis techniques to discover the shortest paths in different cerebral networks, examines the influence of the hematocrit variations on blood flow distribution at the upstream and the downstream regions, and identifies the change of the hematocrit level considering the depth of the network from the pial surface; furthermore, the research incorporates the brain vascular visualization as the post-processing step of the calculations, utilizing several open-source visualizing software to depict the blood flow patterns and the brain territories. Moreover, the tracer convection method is applied to enhance the understanding of the microcirculation level's transport phenomena. Finally, the research addresses the strategies in comprehensive data visualization related to the brain vessels, including the arteries, venous, and cortex. The study contributes to a better understanding and insight into cerebral blood flow dynamics and structure in the brain microvascular.