Low wall shear stress is independently associated with the rupture status of middle cerebral artery aneurysms.

BACKGROUND AND PURPOSE We determined which hemodynamic parameter independently characterizes the rupture status of middle cerebral artery (MCA) aneurysms using computational fluid dynamics analysis. METHODS In 106 patient-specific geometries of MCA aneurysms (43 ruptured, 63 unruptured), morphological and hemodynamic parameters were compared between the ruptured and unruptured groups. Multivariate logistic regression analysis was performed to determine parameters that independently characterized the rupture status of MCA aneurysms. RESULTS Univariate analyses showed that the aspect ratio, wall shear stress (WSS), normalized WSS, oscillatory shear index, WSS gradient, and aneurysm-formation index were significant parameters. The size of the aneurysmal dome and the gradient oscillatory number were not significantly different between the 2 groups. With multivariate analyses, only lower WSS was significantly associated with the rupture status of MCA aneurysms. CONCLUSIONS WSS may be the most reliable parameter characterizing the rupture status of MCA aneurysms.