Direct Numerical Simulation of Transitional Flow in a Patient-Specific MCA Aneurysm

Stroke is a leading cause of death in the Western world (1). One reason for stroke is the rupture of aneurysms usually found in or near the Circle of Willis, an arterial network located at the base of the brain. It is estimated that 1–6% of the population harbor aneurysms during their lifetime (2), and that the average risk of rupture is 1–2% annually. The initiation, growth, and rupture of intracranial aneurysms are complex and multi-factorial processes. The precise mechanism however, is still not known. If the wall shear stress (WSS) exceeds a limit of 40 Pa, the endothelial cells are believed to be damaged, and an aneurysm might form (3) (4).