[Hemodynamic analyses of large intracranial aneurysms]

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Medical Imaging

Background:

• Large intracranial aneurysms pose significant risks, and understanding their hemodynamics is crucial for treatment.
• Previous studies have explored aneurysm hemodynamics, but detailed classification and simulation are ongoing.

Purpose of the Study:

• To computationally simulate the hemodynamics of large intracranial aneurysms.
• To analyze and classify the hemodynamic characteristics of three distinct types of large intracranial aneurysms.

Main Methods:

• Constructed 32 patient-specific models from digital subtraction angiography (DSA) data.
• Classified aneurysms into Type A, B1, and B2 based on outflow vessel location, vortex plane, and impact zone.
• Utilized computational fluid dynamics (CFD) with ICEM and Fluent software, assuming laminar, incompressible, Newtonian blood flow with pulsatile inlet conditions.

Main Results:

• Analyzed wall shear stress, velocity, and streamlines during the cardiac cycle.
• Velocity ratios: Type A (0.186 ± 0.019), B1 (0.706 ± 0.077), B2 (0.208 ± 0.041).
• Wall shear stress ratios: Type A (0.081 ± 0.029), B1 (1.019 ± 0.139), B2 (0.103 ± 0.031). Type B1 exhibited the highest flow velocity and wall shear stress.

Conclusions:

• The location of the impact zone and outflow vessel significantly influences blood flow within the aneurysm sac.
• Inflow angle also plays a role in determining intra-aneurysmal blood flow levels.
• Hemodynamic patterns vary distinctly among the classified aneurysm types, impacting clinical considerations.