The effect of aneurysm geometry on the intra-aneurysmal flow condition

Various anatomical parameters affect on intra-aneurysmal hemodynamics. Nevertheless, how the shapes of real patient aneurysms affect on their intra-aneurysmal hemodynamics remains unanswered.

Quantitative computational fluid dynamics simulation was conducted using eight patients' angiograms of internal carotid artery-ophthalmic artery aneurysms. The mean size of the intracranial aneurysms was 11.5 mm (range 5.8 to 19.9 mm). Intra-aneurysmal blood flow velocity and wall shear stress (WSS) were collected from three measurement planes in each aneurysm dome. The correlation coefficients (r) were obtained between hemodynamic values (flow velocity and WSS) and the following anatomical parameters: averaged dimension of aneurysm dome, the largest aneurysm dome dimension, aspect ratio, and dome-neck ratio.

Negative linear correlations were observed between the averaged dimension of aneurysm dome and intra-aneurysmal flow velocity (r= -0.735) and also WSS (r= -0.736). The largest dome diameter showed a negative correlation with intra-aneurysmal flow velocity (r= -0.731) and WSS (r= -0.496). The aspect ratio demonstrated a weak negative correlation with the intra-aneurysmal flow velocity (r= -0.381) and WSS (r= -0.501). A clear negative correlation was seen between the intra-aneurysmal flow velocity and the dome-neck ratio (r= -0.708). A weak negative correlation is observed between the intra-aneurysmal WSS and the dome-neck ratio (r= -0.392).

The aneurysm dome size showed a negative linear correlation with intra-aneurysmal flow velocity and WSS. Wide-necked aneurysm geometry was associated with faster intra-aneurysmal flow velocity.