Hemodynamic Simulations of Intracranial Aneurysms Using Complex Vascular Models
Overview
This study investigates the impact of vascular model complexity on intracranial hemodynamics by utilizing high-resolution 7T ToF MRI data to create patient-specific Circle of Willis (CoW) geometries with up to 60 outlets. Simulations comparing complex and trimmed models, including pathological variants with intracranial aneurysms, reveal significant differences in flow and shear parameters relevant to aneurysm assessment.
Background
The Circle of Willis (CoW) is a critical intracranial vascular structure often involved in aneurysm formation, which can have fatal consequences if ruptured. Variability in vascular anatomy necessitates patient-specific hemodynamic analysis to understand cerebral blood flow and aneurysm pathophysiology. Prior computational fluid dynamics (CFD) studies have been limited by simplified geometries and few outlets, restricting the accuracy of flow simulations. Advances in high-resolution imaging now enable detailed segmentation of complex vascular trees, allowing more realistic modeling of cerebral hemodynamics.
Data Highlights
Model
Number of Outlets
Cell Count (million)
Physiological Complex
60
4.7
Physiological Trimmed
10
2.5
Pathological Complex
60
6.3
Pathological Trimmed
10
2.6
Key Findings
High-resolution 7T ToF MRI enabled segmentation of a complex CoW model with 60 outlets, surpassing typical CFD models with fewer outlets.
Simulations on complex models showed more accurate representation of intra-vessel and intra-aneurysmal flow patterns compared to trimmed models.
Inclusion of two patient-specific intracranial aneurysms in the models demonstrated clinically relevant flow alterations influenced by vascular complexity.
Complex models required higher computational resources due to increased mesh cell counts but provided enhanced detail in wall shear stress and oscillatory shear metrics.
Trimmed models, representing current standard practice, may underestimate hemodynamic parameters critical for aneurysm risk assessment.
Clinical Implications
Incorporating detailed vascular geometries with multiple outlets in hemodynamic simulations can improve the accuracy of intracranial aneurysm assessment, potentially aiding in risk stratification and treatment planning. High-resolution imaging and advanced segmentation techniques should be considered to capture patient-specific vascular complexity. Clinicians and neuroradiologists may benefit from integrating such detailed CFD analyses into diagnostic workflows to better understand aneurysm behavior.
Conclusion
This study highlights the importance of vascular model complexity in accurately simulating intracranial hemodynamics, particularly in the presence of aneurysms. Utilizing high-resolution imaging to create detailed CoW geometries enhances the fidelity of flow simulations, which may improve clinical evaluation of aneurysm risk.
References
Perosa et al. 2020 -- Influence of hippocampal vascularization patterns on cognitive performance
MATCH Study 2019 -- Patient-specific intracranial aneurysm data
