HEMODYNAMICS AND STRESS DISTRIBUTION IN A CEREBRAL ANEURYSM PARTIALLY BLOCKED WITH COILS

Stroke due to subarachnoid haemorrhage from ruptured cerebral aneurysms is one of the highest causes of death and economic burden in our society. Aneurysms can be treated by placing coils in the aneurysm to alter the local hemodynamics and lower the wall shear stresses to make the aneurysmal flow inactive. Although velocity measurements have been previously made in models of cerebral aneurysms, no specific information is available for the stress distribution inside lateral aneurysms. A three-dimensional Computational Fluid Dynamics (CFD) model was used to investigate the hemodynamics of a pear shaped lateral cerebral aneurysm partially blocked with coils. Stress distribution for different coil locations inside the aneurysm was investigated by using uni-directional Fluid Structure Interaction (FSI). The wall pressure obtained from the CFD was used as a boundary condition for structural analysis. The results were analysed in terms of inflow rate, wall shear stress, apparent viscosity and effective (Von-Mises) stress. The predictions showed areas of the aneurysm that experience high stress. CFD has been shown to be a valuable tool that could help predict which aneurysms would require additional treatment. NOMENCLATURE q constant r radius of the parent vessel α Womersley number γ shear rate λ constant μ coefficient of viscosity αμ constant oμ constant ν kinematic viscosity vonσ Von-Mises stress 1σ, 2σ, 3σ principal stresses ω angular velocit