Acute Ischemic Stroke (AIS) is an abrupt onset of a focal neurological deficit due to the occlusion of a cerebral artery caused by thrombosis or embolism. According to the World Health Organization, stroke is the second leading cause of death in the world. One of the available treatments is the aspiration thrombectomy, where a negative pressure is applied to the thrombus in order to remove it from the vessel. In this work, the aspiration thrombectomy will be studied through the development of a computational model. By means of the development of this model, a baseline is created for exploratory research into both the technical and clinical aspects. The range of applied thrombus models in literature varies largely. In this work, the thrombus is modelled using a fluid material model. Through the application of this fluid model, an emphasis is put on the fluid properties of thrombi, which exhibit both solid and fluid behavior. Three fluid models are applied, of which two represent non-Newtonian fluid behavior and one Newtonian fluid behavior. The effects of these material models are assessed through the pressure and velocity distribution and the thrombus behavior. Furthermore, an evaluation of three clinical parameters, aspiration pressure, suction distance and thrombus length, is performed. Each parameter was assigned three variations, which are assessed based on the respective recanalization times. Each clinical parameter is evaluated to influence the recanalization time, albeit to different extents. In conclusion, this thesis functions as exploratory research in the development of computational aspiration thrombectomy models. Future research is advised, in the form of material model verification with patient-retrieved or analog clots or more extensive research into the relation between recanalization time and the presented clinical parameters.

An acute ischemic stroke is one of the leading causes of death and is caused by a thrombus that occludes a cerebral artery. This thrombus reduces the cerebral blood flow and causes irreversible brain tissue damage. Mechanical thrombectomy is a safe and effective technique to remove the thrombus from the cerebral arteries and restore the brain's blood flow. The mechanical properties of the thrombus highly influence the success rate of mechanical thrombectomy. To investigate the mechanical behavior of the thrombus under different loading conditions, numerical simulations could be performed. The aim of this thesis is to develop an in silico thrombus model to investigate the mechanical behavior of the thrombus under compressive and tensile loading conditions using finite element analysis software LS-DYNA. Experimental data collected from the lab is used to describe the mechanical behavior in the numerical thrombus models. The building process of the in silico models in this study is organized in three parts. Part one is the cube model, where the material properties and numerical stable settings are investigated. Also, a combination of compression and tension is applied to the cube model to capture both the compressive and tensile forces present during mechanical thrombectomy. Part two includes geometry models that mimic the clot analog samples' geometry used during the experimental compression and tensile tests. Part three includes a clot analog with an initial hole in the middle to understand the fracture behavior of the thrombus. Different approaches to model fracture of the thrombus are investigated. Three different parts characterize this thesis, and each includes a method, results, and discussion section. The discussion section of each part is dedicated to the decisions that have been made in that specific chapter. A discussion section is also included in the chapter Experiments. The general discussion at the end of this study will include the findings of each model and the comparison with literature. Recommendations for further research are given at the end. In conclusion, this study provides a framework for modeling the thrombus under tensile and compressive loading, where the thrombus is modeled as a hyperelastic material. Future work is advised to extend and improve the models developed in this study.