Analysis of hemodynamic changes from aneurysm inception to large sizes

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Neurosurgery

Background:

• Cerebral aneurysm progression and rupture risk factors are known, but evolution of flow dynamics remains unclear.
• Understanding hemodynamic changes is crucial for predicting aneurysm behavior.

Purpose of the Study:

• To analyze changes in cerebral aneurysm hemodynamic environment during growth.
• To compare flow characteristics between fixed and growing aneurysm necks.

Main Methods:

• Image-based computational fluid dynamics (CFD) applied to 88 aneurysms.
• Simulated aneurysm geometry evolution with fixed vs. growing necks.
• Quantitative comparison of flow parameters like velocity and wall shear stress.

Main Results:

• Inflow rate varied: increased with growing necks, decreased with fixed necks.
• Inflow jet concentrated; mean velocity and wall shear stress decreased in both scenarios.
• Intra-aneurysmal flow complexity and instability increased; low wall shear stress areas expanded.

Conclusions:

• Aneurysm neck evolution significantly impacts hemodynamic changes.
• Fixed neck aneurysms may reach stable flow states faster than growing neck aneurysms.
• Growing necks might evolve towards more unfavorable hemodynamic conditions.