Computational analysis of hemodynamics using a two-dimensional model in moyamoya disease
Ho Jun Seol1, Duk Chul Shin, Yoo Seok Kim
1Department of Neurosurgery, Kangwon National University, Chuncheon, South Korea.
Object:
Bilateral intimal thickening of the distal internal carotid arteries (ICAs) and the development of many collateral vessels in the base of the brain characterize moyamoya disease (MMD). Although the etiology of and the reason why MMD is limited to the major intracranial vessels remain unclear, flow dynamics, such as shear stress, may be related to its smooth-muscle cell migration. Therefore, this study was performed to determine the local hemodynamic factor, which concerns the predominance of specific anatomical sites, such as the distal ICA in the early stage and the proximal posterior cerebral artery (PCA) in the advanced stage of MMD.
Methods:
The authors simulated the hemodynamics in the circle of Willis using computational models of 2D geometries of the distal ICA and PCA. A finite-element commercial package, automatic dynamics incremental nonlinear analysis (ADINA), was used to simulate blood flow in these arteries.
Results:
Numerical results demonstrated that shear stress was relatively low at the ICA region. The distribution of shear stress was related to the predisposing area of MMD.
Conclusions:
Diminished shear stress may promote stenosis of the distal ICA, which is a major pathological region in MMD.
Insights
Low shear stress in the internal carotid artery (ICA) may contribute to moyamoya disease (MMD) development. This study simulated blood flow to understand hemodynamic factors in MMD progression.
Area of Science:
- Neurology
- Biomedical Engineering
- Cardiovascular Research
Background:
- Moyamoya disease (MMD) is characterized by bilateral intimal thickening of distal internal carotid arteries (ICAs) and collateral vessel development.
- The exact etiology of MMD and its predilection for major intracranial vessels remain unclear.
- Flow dynamics, specifically shear stress, are hypothesized to influence smooth-muscle cell migration in MMD.
Purpose of the Study:
- To investigate the role of local hemodynamic factors in MMD.
- To determine the relationship between shear stress distribution and the anatomical sites affected in MMD, such as the distal ICA and proximal posterior cerebral artery (PCA).
Main Methods:
- Computational fluid dynamics (CFD) models were used to simulate hemodynamics in the circle of Willis.
- 2D geometries of the distal ICA and PCA were analyzed.
- The finite-element commercial package, ADINA, was employed for blood flow simulation.
Main Results:
- Numerical simulations revealed relatively low shear stress in the ICA region.
- The distribution patterns of shear stress correlated with the predisposing areas observed in MMD.
Conclusions:
- Diminished shear stress is a potential contributing factor to the stenosis observed in the distal ICA, a key pathological site in MMD.
- Hemodynamic factors, particularly shear stress, play a significant role in the pathogenesis of moyamoya disease.
