Table I.

Definition of different hemodynamic quantities proposed to evaluate possible initiation site of aneurysms. All temporal integrations are calculated over the cardiac cycle T.

Quantity	Definition	Notes
OSI	$\frac{1}{2}\left\{1-\frac{\mid {\int }_0^T{\mathit{f}}_{i}dt\mid }{{\int }_0^T\mid {\mathit{f}}_i\mid dt}\right\}$	f i is the instantaneous wall shear stress
AFI	$\frac{{\mathit{f}}_i·{\mathit{f}}_{av}}{\mid {\mathit{f}}_i\mid \mid {\mathit{f}}_{av}\mid }$	f av is the time averaged wall shear stress
GON	$\frac{1}{2}\left\{1-\frac{\mid {\int }_0^T\mathit{G}dt\mid }{{\int }_0^T\mid \mathit{G}\mid dt}\right\}$	$\mathit{G}=\left(\frac{\partial f_p}{{\partial }_p},\frac{\partial f_q}{{\partial }_q}\right)$ is the spatial wall shear stress gradient, where the p-direction corresponds to the time-averaged direction of the f vector over the flow cycle and the q-direction is perpendicular to p.