Wall Shear Stress Fluctuations due to Flow Instability in Intracranial Aneurysms

Experimental studies of an impingement area inside aneurysms showed that loss of smooth muscle cells and degenerative remodeling of vessel walls occur at the region of high wall shear stress (WSS) and WSS gradient where the flow accelerates [1]. Also, a more sensitive response of endothelial cells to turbulent oscillatory shear rather than to laminar and steady shear has been demonstrated experimentally [2]. Therefore, it seems imperative to understand the spatio-temporal behavior of WSS vectors in the impingement (stagnation) locations. To this end, we investigate systematically the oscillatory behavior of WSS vectors inside aneurysms and the flow instability due to the presence of an aneurysm in the internal carotid arteries (ICA), more specifically, at the posterior communicating artery (PCoA) origin.