External forces, accelerations and displacements, due to sudden motions of head or traumas, may affect the haemodynamics and flow patterns in a cerebral aneurysm. Despite several studies on blood flow dynamics and arterial wall mechanics in intracranial aneurysms, limited investigations considered the external forces or motion of the arterial wall. Therefore in this study, we have numerically analyzed the effects of wall movement on cerebral aneurysms with the fluid and structure interaction (FSI) theories. A 3Dimentional Model of Middle Cerebral Artery (MCA) aneurysm (geometry adopted from R. Torii et al., Int. J. Numerical Methods in Fluids, 54:995–1009, 2007) was constructed and exposed to a realistic head motion in sagital plane. Blood was considered as a homogeneous, incompressible and Newtonian fluid and arterial wall assumed to be elastic, incompressible and isotropic. The governing equations were, continuity and Navier-Stokes equations for fluid domain and equilibrium equations and Hooke’s Law for arterial wall. The flow was steady and motion was applied to the arterial wall. Simulations were carried out using the commercially availed finite element software. The effect of wall motion on flow patterns and wall shear stress, strain and effective stress distributions have been discussed. The results show that arterial wall motion doesn’t change the magnitude of major hemodynamic factors and wall stress and strain distributions considerably and won’t lead to aneurismal rupture directly, but obviously affects the blood flow patterns in cerebral aneurysms.

Figure 1

Velocity vectors in model with arterial wall motion

Figure 2

Effective stresses distribution in model with artery wall motion