Morphological Effect on Wall Shear Stress in Intracranial Aneurysms.

Both high and low wall shear stress (WSS) play important roles in the development and rupture of intracranial aneurysms (IAs). This study aimed to determine the morphological factors that affect WSS in the IA and the parent artery. We studied a total of 66 IAs with three-dimensional imaging. Computational fluid dynamics (CFD) models were constructed and used to characterize the hemodynamics quantitatively. Aneurysms were grouped according to the mean neck width. The associations among hemodynamics and morphology were analyzed. Aspect ratio was correlated to lowest WSS (r = - 0.576), aneurysm-to-parent vessel (A-P) WSS ratio (r = - 0.500), and lowest-parent vessel (L-P) WSS ratio (r = - 0.575). Height-to-width ratio and height were correlated to WSS. Mean aneurysm WSS (p = 0.023), lowest WSS (p < 0.0001), highest-to-lowest WSS ratio (p = 0.004), L-P WSS ratio (p < 0.0001), highest-parent vessel (H-P) WSS ratio (p = 0.008), A-P WSS ratio (p < 0.001), and height (p < 0.001) were different between the two groups of aneurysms that were divided by the relationship between the diameters of the aneurysms and the necks. Multivariable analysis showed that the lowest WSS (p = 0.028) and A-P WSS ratio (p = 0.001) were independently associated with neck width. Morphological characteristics are associated with IA and parent vessel WSS. Aneurysms with different neck widths have different hemodynamics. These results could help in understanding the progression of IA and in building predictive models for IA rupture.