THESIS
2016
xiii, 131 pages : illustrations (some color) ; 30 cm
Abstract
Thrombus plays an important role in the progression, rupture and healing of cerebral aneurysms. Nowadays, cerebral aneurysms are usually treated with endovascular techniques including coiling and flow-diverting, which are targeted to cause flow stasis inside aneurysm sac and induce intra-aneurysmal thrombosis followed by shrinkage of the sac as thrombus develops. Computational fluid dynamics has been used to investigate hemodynamics inside aneurysms before and after treatment. However, most studies in literature focus only on hemodynamic parameters, neglecting the biochemistry behind thrombus formation. In this study, we proposed a new computational model coupling both hemodynamics and biochemical reactions to explain stasis-induced thrombosis in aneurysms. The model predicted a thresho...[
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Thrombus plays an important role in the progression, rupture and healing of cerebral aneurysms. Nowadays, cerebral aneurysms are usually treated with endovascular techniques including coiling and flow-diverting, which are targeted to cause flow stasis inside aneurysm sac and induce intra-aneurysmal thrombosis followed by shrinkage of the sac as thrombus develops. Computational fluid dynamics has been used to investigate hemodynamics inside aneurysms before and after treatment. However, most studies in literature focus only on hemodynamic parameters, neglecting the biochemistry behind thrombus formation. In this study, we proposed a new computational model coupling both hemodynamics and biochemical reactions to explain stasis-induced thrombosis in aneurysms. The model predicted a threshold response of thrombosis to shear rate, of which the critical value to trigger coagulation was found to be close to values reported in published
literature. A threshold value for fibrin concentration was also identified by simulated prothrombin test in the study. The model has been verified by animal experiments. The fibrin distributions in a ligated right common carotid artery predicted by the model were in good agreement with experimental results obtained from rats. Spontaneous thrombosis in aneurysms has also been studied with the model. Larger size, narrower neck width, larger dome height and straight parent artery have been identified to favor thrombosis in aneurysm. A height-to-neck aspect ratio of 1.6 has been found to be a critical value to discriminate aneurysms with or without thrombosis. The model has also demonstrated its capability of predicting treatment outcomes of flow diversion in cerebral aneurysms, consistent with angiographic observations from clinical follow-up. This novel computational model can serve as a tool for clinicians to evaluate treatment outcome pre-operatively, facilitating the process of medical decision making and surgical planning.
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