| Part one:Establishment of patient-specific numerical intracranial aneurysm model and analysis of hemodynamicsObjective: To establish a numerical model of patient-specific intracranial aneurysm based on 3D rotation angiography image and analyze the hemodynamic characters of the aneurysm .Methods: The 3DRA image of one rupture intracranial aneurysm was transferred into 3DMAX then GEOMAGIC for being segmented and smoothed surface data. The surface data was imported into ANSYS CFD in order to create finite element grids. After meshing, we applied ANSYS CFX to create configuration files for fluid field computations and structural mechanics computations respectively, which include the setting of material properties, boundary condition and time step. At last we obtained the hemodynamic parameters including wall shear stress, streamline, velocity profile and pressure profile.Results: We analyzed hemodynamic characters of the intracranial aneurysm including WSS distribution, maximum WSS, streamline, intra-aneurysmal flow pattern, velocity profile, velocity and width of inflow jet, location and size of impaction zone.Conclusion: The 3DRA image of intracranial aneurysm can be used to create finite element grids. With computational fluid dynamics we can tell the hemodynamic characters of the intracranial aneurysm more directly and clearly. Part two:Comparison of hemodynamics characteristics in rupture and unrupture intracranial aneurysms in different patients with computational fluid dynamics: a paring researchObjective: To investigate the different hemodynamic characters in rupture and unrupture intracranial aneurysms in various patients and to characterize possible associations with rupture.Methods: We studied 12 consecutive patients with unrupture intracranial aneurysms and other 12 pairing patients with rupture intracranial aneurysms. Based on 3D rotation angiography images, 24 numerical models of patient-specific intracranial aneurysms were created then analyzed the hemodynamic characters respectively. We focused on the WSS distribution, maximum WSS, width and maximum velocity of inflow jet, location and size of impaction zone, intra-aneurysmal flow pattern.Results: In both group, there were 10 wide-neck aneurysms in the total 12 ones. In the different patients paring research, there was significant statistic difference in the maximum velocity of inflow jet, size of impaction zone between the rupture aneurysms group and the unrupture aneurysms group (P=0.031;P=0.001). There was no significant statistic difference in the maximum WSS, width of inflow jet, location of impaction zone and intra-aneurysmal flow pattern between the two groups (P=0.791;P=0.716;P=1.000;P=0.195).Conclusion: Aneurysms with higher inflow rates and small impaction zones are associated with a clinical history of rupture. Part three:Comparison of hemodynamics characteristics in rupture and unrupture intracranial aneurysms in same patient with computational fluid dynamics: a paring researchObjective: To investigate the different hemodynamic characters in rupture and unrupture intracranial aneurysms in various patients and to characterize possible associations with rupture.Methods: We studied 87 consecutive patients with multiple intracranial aneurysms and subarachnoid haemorrhage then focused on the 20 patients among them, whose aneurysm could be defined with rupture or unrupture. The rupture and unrupture aneurysms in the same patient were pairing. Based on 3D rotation angiography images, 40 numerical models of patient-specific intracranial aneurysms were created then analyzed the hemodynamic characters respectively. We studied on the WSS distribution, maximum WSS, width and maximum velocity of inflow jet, location and size of impaction zone, intra-aneurysmal flow pattern.Results: In both group, there were 19 wide-neck aneurysms in the total 20 ones. In the same patients paring research, there was significant statistic difference in the maximum velocity of inflow jet, size of impaction zone and intra-aneurysmal flow pattern between the rupture aneurysms group and the unrupture aneurysms group (P=0.002;P<0.0001;P=0.0007). There was no significant statistic difference in the maximum WSS, width of inflow jet and location of impaction zone between the two groups (P=0.985;P=0.917; P=0.795). We also found the WSS distribution was more complicated in the rupture aneurysms than in the unrupture ones.Conclusion: Aneurysms with higher inflow rates, small impaction zones and disturbed intra-aneurysmal flow patterns are associated with a clinical history of rupture. The WSS distribution may be a possible association with rupture. Paring research shows great role in assessing risk of rupture on intracranial aneurysms.
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