Experimental Study of the Vascular Dynamics of a Saccular Basilar Aneurysm

A majority of patients who suffer hemorrhaging as a result of a ruptured cerebral aneurysm experience reduced quality of life, long term brain damage, or death. Improved understanding of the flow patterns in cerebral aneurysms will lead to better techniques for their detection and treatment. Experiments are conducted in a generic flow phantom to characterize the basic behavior of blood flow in basilar saccular aneurysms. The test setup models a saccular aneurysm that forms at the bifurcation of the basilar artery into the Circle of Willis. Three input flow conditions are tested: a physiological flow waveform obtained from Kato (2002) [1] and two steady flow conditions corresponding to the peak and mean flow rates of the physiological flow waveform. Steady cases are examined to study the effect of increasing Reynolds number on the flow and the pulsatile case to quantify unsteady effects. The results reveal highly three dimensional flow patterns within the aneurysm. Velocity and vorticity fluctuations are extracted to investigate the nature of the unsteady flows. Wall shear stress is estimated around the aneurysm dome to examine its role in wall weakening and failure.