Background Aneurysm hemodynamics has been shown to be an important factor in aneurysm growth and rupture. Although pulsatility is essential for blood flow and vascular wall function, studies of pulsatile flow properties in brain aneurysm disease are limited.

Objective To investigate differences in pulsatility within a group of ruptured and unruptured aneurysms by implementing patient-specific pulsatile flow simulation.

Methods 41 of 311 internal carotid artery aneurysms were selected from an aneurysm database (29 unruptured and 12 ruptured) and used for patient-specific hemodynamic simulations of pulsatile flow. Flow pulsatility changes in ruptured and unruptured groups were analyzed by comparing different components of blood flow. Pulsatility index (PI) was used to quantify the pulsatility of blood flow in each group at the aneurysm neck, body, dome, and parent artery.

Results Within the parent artery, PI did not significantly differ between ruptured and unruptured groups (0.58). Within unruptured aneurysms, values of PI similar to that of the parent artery were found (0.61). Trends of significantly higher PI (1.99) were found within ruptured aneurysms (p<0.001). These differences were localized at the aneurysm neck, where PI in ruptured (1.93) and unruptured (0.59) aneurysms was significantly different (p<0.001).

Conclusions A trend towards a lower PI, similar to that in the parent artery, was found in unruptured aneurysms, while ruptured aneurysms followed a trend of higher pulsatility. The difference was significant at the aneurysm neck, indicating that pulsatility and this location may be important aspects of aneurysm rupture and a useful predictor of the risk of aneurysm rupture.