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The objective of this study is to investigate the hemodynamics in patient-specific internal carotid aneurysm and discuss the reason for rupture of aneurysm. A 3-Dimensional pulsatile blood flow in internal carotid with a sidewall aneurysm was studied numerically with the average Reynolds number of 704. Patient-specific model whose parent artery has a large "S" bending and a sidewall aneurysm was constructed from CT data. Unsteady, incompressible, 3-Dimensional Navier-Stokes equations were employed to solve the flow field. The temporal distributions of hemodynamic variables during the cardiac cycle such as streamlines, wall pressure and wall shear stress (WSS) in the arteries and aneurysm were analyzed. From streamlines it can be found that there is an obvious vortex flow in aneurismal cavity in a cardiac cycle. The type of this vortex flow is not changed in a cardiac cycle. As far as Wall Shear Stress, there is a region in aneurismal neck where the value of WSS is relatively high. Growth and rupture mechanism of internal carotid aneurysm in patient can be analyzed based on patient-specific model and hemodynamics simulation.

An intracranial aneurysm (IA) is a pathological dilatation of the cerebral artery wall. Blood flow and pressure inside IA are not steady. Interaction between blood flow and vessel wall reveals stress and deformation of vessel wall in vivo. It also provides more true and reliable information about blood flow. So analysis of Fluid Structure Interaction (FSI) is favor of proper explanation for formation and development of aneuris-mal disease. Patient-specific model whose parent artery has a large “S” bending and a side wall aneurysm was constructed from CT data. Pulsatile calculation of FSI for this constructed model was carried out. From streamlines it can be found that there is an obvious vortex flow in aneurismal cavity in a cardiac cycle. The type of this vortex flow is not changed in a cardiac cycle. As far as Wall Shear Stress (WSS), there is a region in aneurismal neck where the value of WSS is relatively high. At 0.27s in a cardiac cycle, deformation of the vessel wall is the biggest. There are two regions in aneurismal dome where the value of Von Mises Stress is the locally biggest.

In order to identify the border of STL model with open border, topology structure of STL model was reconstructed using half edge data structure. On this basis, border segments of STL model can be identified by a process of edge traversing. Then constrained Delaunay triangulation with Steiner point insertion was used to triangulate the border regions of STL model. In this way, STL model was closed and it provides necessary foundation to further finite element mesh generation.