Three dimensional finite-element modeling of blood flow in elastic vessels: effects of arterial geometry and elasticity on aneurysm growth and rupture

An intracranial aneurysm (ICA) is the localized dilated of cerebral arterial segment due to a degenerative arterial disease causing local wall weakness. Sudden ICA rupture of cerebral aneurysms is the leading cause of subarachnoid haemorrhage (SAH) which is a serious disease associated with high mortality and morbidity. In this research work, we have developed and validated a finite-element fluid-structure interaction (FSI) 2-way coupling model using COMSOL Multiphysics® software package. We applied the model to three idealized intracranial elastic arteries under the Newtonian blood flow assumption. The blood flow was characterized as a steady flow velocity at the inflow and various values of blood pressure at the outflow, while the arterial wall was modeled as a hyperelastic neo-Hookean material. The result shows the significantly weakened wall shear stress (WSS) at the aneurysm fundus and intensified WSS at the distal side of aneurysm neck. The wall deformation and WSS may play an important role in the growth and rupture of ICAs. Moreover, based on these results we postulate that lateral saccular aneurysms located on highly curved arteries are subjected to higher hemodynamic stresses and are more prone to rupture.