Flow-Induced Wall Mechanics of Patient-Specific Aneurysmal Cerebral Arteries: Nonlinear Isotropic vs. Anisotropic Wall Stress

There are several biomechanical factors involved in the formation, growth, remodeling, and eventual rupture of intracranial aneurysms. In particular, hemodynamic forces have a decisive role in the biomechanical environment of the aneurysmal cerebral vasculature. Most of the previous studies on vascular mechanics assessment of intracranial aneurysms are based on idealized geometries, where it has been suggested [1] that it is highly unlikely that saccular aneurysms expand due to a limit point instability. In addition, it has been reported [2] that some saccular aneurysms with non-spherical initial shape tend to become spherical when subjected to uniform pressure, because a spherical geometry is optimal to resist the pressure load, yielding a homogenous wall stress. In the present work, we present a comparison between anisotropic and isotropic constitutive models, which allows us to analyze the biomechanics of patient-specific cerebral aneurysmal arteries subjected to flow-induced pulsatile pressure. The results describe the effects of material anisotropy in the resulting wall mechanics of the intracranial vasculature geometries.