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Hemodynamics and bleb formation in intracranial aneurysms
J R Cebral1, M Sheridan, C M Putman
1Center for Computational Fluid Dynamics, Department of Computational and Data Sciences, College of Sciences, George Mason University, Fairfax, Virginia 22030, USA. jcebral@gmu.edu
AJNR. American Journal of Neuroradiology
|October 3, 2009
Summary
Blebs on cerebral aneurysms form near high wall shear stress (WSS) regions and align with blood flow. Their formation leads to lower WSS and vortex formation, suggesting elevated WSS contributes to bleb development.
Area of Science:
- Neurosurgery
- Biomedical Engineering
- Fluid Dynamics
Background:
- Intracranial aneurysms with irregular shapes, blebs, or secondary outpouchings are linked to increased rupture risk.
- Understanding the factors contributing to bleb formation is crucial for predicting aneurysm rupture.
Purpose of the Study:
- To investigate the association between local hemodynamics and the formation of blebs in cerebral aneurysms.
- To explore the role of wall shear stress (WSS) and intra-aneurysmal flow patterns in bleb development.
Main Methods:
- Computational models of 20 cerebral aneurysms with 30 blebs were created from 3D angiographies.
- Models simulated aneurysm hemodynamics before and after bleb formation using computational fluid dynamics (CFD) under pulsatile flow.
- Flow and WSS visualizations analyzed hemodynamics in bleb regions.
Main Results:
- 80% of blebs formed at or adjacent to regions of highest WSS before formation, near flow impaction zones.
- 83% of blebs developed in areas of high/moderate WSS, transitioning to low WSS after formation.
- 77% of blebs aligned with the inflow jet, indicating a relationship with intra-aneurysmal flow structures.
Conclusions:
- Blebs originate in high WSS areas and align with major intra-aneurysmal flow.
- Bleb formation leads to reduced WSS and counter-current vortex development.
- Locally elevated WSS may contribute to the focal wall damage initiating bleb formation.
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