Hemodynamic Features of Rupture-Prone Blebs in Ruptured Intracranial Aneurysms: A Computational Fluid Dynamics Study

Blebs on ruptured intracranial aneurysms are presumed rupture sites, yet the hemodynamic signature of rupture-prone blebs remains incompletely defined. Using computational fluid dynamics, we investigated the hemodynamic features of blebs in ruptured aneurysms in which rebleeding was prevented by intentional bleb coil embolization.

Of 106 patients with intracranial aneurysm rupture who underwent coil embolization at our hospital between January 2018 and December 2024, we retrospectively analyzed the data of those who were treated with intentional bleb coil embolization and experienced no rebleeding. Computational fluid dynamics analyses were performed retrospectively to characterize pressure and time-averaged wall shear stress (WSS) distributions in the aneurysms.

Six aneurysms (5.6%; 4 anterior communicating arteries, 1 internal carotid artery, and 1 middle cerebral artery) were analyzed. No rebleeding occurred in any of the aneurysms. In all aneurysms, maximum pressure with flow impingement was observed at the neck of the bleb, inducing increased pressure inside the bleb. Moreover, minimum time-averaged WSS in the aneurysm dome was identified at the bleb (0.68 ± 0.45 Pa).

Aneurysmal blebs with hemodynamic features of maximum pressure with flow impingement and minimum time-averaged WSS have the potential to rupture. These features may help identify the highest-risk rupture point, which is a target of blood flow blockage by coil embolization.