Intracranial aneurysms are pathological dilations of the cerebral arterial wall, typically occurring at arterial bifurcations where hemodynamic stress is concentrated.

Computational fluid dynamics (CFD) studies suggest that the following factors may contribute to aneurysm initiation:

• High wall shear stress (WSS) → may damage endothelial cells
• Flow bifurcations → increase mechanical stress on vessel walls
• Complex or unstable flow patterns → lead to endothelial dysfunction
• Low WSS zones → promote inflammation, wall remodeling and degeneration

CFD findings are integrated with biological hypotheses:

• Endothelial injury triggers inflammatory cascades
• Smooth muscle cell apoptosis weakens wall structure
• Matrix degradation via MMPs (matrix metalloproteinases)
• Genetic predisposition may modulate vulnerability

• Anterior communicating artery (ACoA)
• Posterior communicating artery (PCoA)
• Middle cerebral artery (MCA) bifurcation
• Internal carotid artery (ICA) siphon