Dispersion Study in a Giant Intracranial Aneurysm Using Computational Fluid Dynamics Techniques

The formation and growth of intracranial aneurysms is partly attributed to various hemodynamic factors such as shear stress and pressure. This issue is further investigated in the present paper using some new insight gained from passive scalar dispersion in the blood flow. Intracranial aneurysms are best visualized using selective catheter angiogram technique where a contrast agent added to the blood flow is visualized and filmed dynamically. In the current study, the 2D threshold images produced by “3D rotational X-ray angiography technique” are used in an ‘in-house’ program to construct a 3D volumetric grid which is then used to calculate the blood flow through the aneurysm. Dispersion of a fluid material with properties similar to that of the contrast agent is also modeled in the blood flow. Unlike previous studies, we investigated the dispersion of a pulsed scalar to better understand the flow dynamics. Results from a large aneurysm are compared to those for a relative small one to show the effect of geometry. The dispersion and flow patterns show the localization of high stress in stagnation areas, which may be the potential regions for the origin and growth of aneurysms. We also investigated the dependence of flow properties on the initial and boundary conditions to calculate the pressure and the wall shear stress values for a given geometry.