Formation and rupture of intracranial aneurysms with blebs: a discriminant study using anatomical and phantom models.

BACKGROUND

Intracranial aneurysms (IAs) with bleb(s) carry a higher risk of rupture. This study aimed to investigate the hemodynamic factors driving bleb formation and subsequent IA rupture using anatomical and phantom models across various bleb scenarios.

METHODS

Anatomical models of 45 IAs with 67 bleb scenarios were reconstructed from 3D rotational angiographies. To study the pre-bleb state, phantom parental models were created by virtually removing the blebs. Hemodynamic characteristics were then evaluated using validated computational methods under physiological pulsatile flow.

RESULTS

Critical hemodynamic indicators illustrate that higher wall shear stress (WSS) was linked to IA rupture at anterior cerebral artery (ACA) bifurcation (p < 0.05), while relatively low WSS was associated with IA rupture on the internal carotid artery (ICA) (p < 0.05). Additionally, bleb initiation is significantly driven by high surface-averaged WSS (p < 0.05) and WSS gradient (p < 0.05) with lower maximum oscillatory shear index (p < 0.05).

CONCLUSIONS

Blebs most likely form near the edge of the original impacted region rather than its center. The specific hemodynamic parameters predicting IA rupture with blebs are highly location-dependent.