Modeling of Flow Through The Circle of Willis and Cerebral Vasculature to Assess The Effects of Changes In The Peripheral Small Cerebral Vasculature on The Inflows

Šutalo, Ilija D.; Bui, Anh; Ahmed, Shakil; Liffman, Kurt; Manasseh, Richard

doi:10.1080/19942060.2014.11083311

Cited by 16 publications

(15 citation statements)

References 3 publications

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“…This simplification may lead to an underestimation of cerebral perfusion as well as an overestimation of the cerebral perfusion impairment [ 39 , 78 – 81 ]. The quantitative impact of the CA in different models, however, are varied [ 82 ]. Thus, our current model based on the assumption of neglecting the CA is still capable of providing information to analyse the aspects the brain circulation.…”

Section: Discussionmentioning

confidence: 99%

The role of the circle of Willis in internal carotid artery stenosis and anatomical variations: a computational study based on a patient-specific three-dimensional model

et al. 2015

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BackgroundThe aim of this study is to provide better insights into the cerebral perfusion patterns and collateral mechanism of the circle of Willis (CoW) under anatomical and pathological variations.MethodsIn the current study, a patient-specific three-dimensional computational model of the CoW was reconstructed based on the computed tomography (CT) images. The Carreau model was applied to simulate the non-Newtonian property of blood. Flow distributions in five common anatomical variations coexisting with different degrees of stenosis in the right internal carotid artery (RICA) were investigated to obtain detailed flow information.ResultsWith the development of stenosis in unilateral internal carotid artery (ICA), the cerebral blood supply decreased when the degree of stenosis increased. The blood supply of the ipsilateral middle cerebral artery (MCA) was most affected by the stenosis of ICA. The anterior communicating artery (ACoA) and ipsilateral posterior communicating artery (PCoA) functioned as the important collateral circulation channels when unilateral stenosis occurred. The blood flow of the anterior circulation and the total cerebral blood flow (CBF) reached to the minimum in the configuration of the contralateral proximal anterior cerebral artery (A1) absence coexisting with unilateral ICA stenosis.ConclusionsCommunicating arteries provided important collateral channels in the complete CoW when stenosis in unilateral ICA occurred. The cross-flow in the ACoA is a sensitive indicator of the morphological change of the ICA. The collateral function of the PCoA on the affected side will not be fully activated until a severe stenosis occurred in unilateral ICA. The absence of unilateral A1 coexisting with the stenosis in the contralateral ICA could be the most dangerous configuration in terms of the total cerebral blood supply. The findings of this study would enhance the understanding of the collateral mechanism of the CoW under different anatomical variations.

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Section: Discussionmentioning

confidence: 99%

The role of the circle of Willis in internal carotid artery stenosis and anatomical variations: a computational study based on a patient-specific three-dimensional model

et al. 2015

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“…The idealized models are built by the computer-aided design (CAD) tools. An idealized model could be a simple one based on limited geometric parameters [47], a local 3D geometry coupled with 0D artery tree at inlet and outlets [48], or a structure rebuilt from the in-vitro model [49,50]. More patient-specifically, some idealized models were reconstructed from the central lines extracted from the clinical imaging of intracranial arteries [51][52][53] or an intact arterial structure starting from the aorta [5], or derived from changing the topology of CoW reconstructed from patientspecific CT images [54].…”

Section: ) Methods To Improve Accuracymentioning

confidence: 99%

“…Boundary conditions are important for 3D CFD simulation. 0D [48,59,62] and 1D models [47] were adopted as boundary conditions in some 3D models. Yamada et al jointed 1D models to the outlets of their 3D model, and attached 0D models to the outlets of 1D models, forming a cascading arterial tree ( Fig 3C) [9].…”

Section: ) Methods To Improve Accuracymentioning

confidence: 99%

“…Compared with 0D and 1D models, in the 3D models more non-Newtonian rheological models have been applied such as the Carreau model [45,53,54], the Carreau-Yasuda model [55], the power-law model [5], the Casson model [47], and more complicated models in which the viscosity was derived from the hematocrit value [9,68].…”

Section: ) Comparison Between 0d 1d and 3d Modelsmentioning

confidence: 99%

“…Hematocrit-based non-Newtonian model [19] Hematocrit-based non-Newtonian models [30,32] Carreau model [45,53,54], Carreau-Yasuda model [55], power-law model [5], Casson model [47], Hematocrit-based non-Newtonian models [9,68].…”

Section: Mainly Newtonian Modelsmentioning

confidence: 99%

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State-of-the-Art Computational Models of Circle of Willis With Physiological Applications: A Review

et al. 2020

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Background: Various computational models of the circle of Willis (CoW) have been developed to non-invasively estimate the blood flow and hemodynamic parameters in intracranial arteries for the assessment of clinical risks such as aneurysms, ischemia, and atherosclerotic plaque growth. This review aims to categorize the latest computational models of CoW and summarize the innovative techniques. Summary of Review: In traditional computational models of CoW, the computational complexity increased from zero-dimensional models to one-dimensional and three-dimensional models. The applications extend from estimating certain hemodynamic parameters to simulating local flow field. The innovative techniques include the combination of models with different dimensions, the extension of vascular structure including heart and veins, as well the addition of distal fractality, cerebral autoregulation, and intracranial pressure. There are some nontraditional models based on fluid-solid-interaction, control theory, and in-vitro experiments. In all kinds of models, the in-vivo data and non-Newtonian rheological models of blood have been widely applied to improve the accuracy of hemodynamic simulation. Conclusion: Firstly, the selection of model depends on its application scenario. The balance between computational complexity and physiological accuracy deserves further investigation. Secondly, the improvement of CoW models relies on the large-scale validations and the combination of various innovative modeling techniques. INDEX TERMS brain modeling, computational modeling, Circle of Willis (CoW), Windkessel effect, pulse wave, computational fluid dynamics (CFD), cerebral blood flow, intracranial arteries.

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The circle of Willis revisited: Forebrain dehydration sensing facilitated by the anterior communicating artery

et al. 2020

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We hypothesize that threat of dehydration provided selection pressure for the evolutionary emergence and persistence of the anterior communicating artery (ACoA – the inter‐arterial connection that completes the Circle of Willis) in early amniotes. The ACoA is a hemodynamically insignificant artery, but, as we argue in this paper, its privileged position outside the blood‐brain barrier gives it a crucial sensing function for the osmolarity of the blood against the background of the rest of the brain, which efficiently protects itself from dehydration. Till now, the questions of why the ACoA evolved, and what its physiological function is, have remained unsatisfactorily answered. The traditional view—that the ACoA serves as a collateral source of vascularization in case of arterial stenosis—is anthropocentric, and not in accordance with principles of natural selection that apply more generally. Diseases underlying arterial stenosis are associated with aging and the human lifestyle, so this cannot explain why the ACoA formed hundreds of millions of years ago and persisted in amniotes to this day. The peculiar hemodynamic properties of the ACoA could be selected traits that allowed for more efficient forebrain detection of dehydration and complex behavioral responses to water loss, a major advantage in the survival of early amniotes. This hypothesis also explains insufficient hydration often seen in elderly humans.

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Modeling of Flow Through The Circle of Willis and Cerebral Vasculature to Assess The Effects of Changes In The Peripheral Small Cerebral Vasculature on The Inflows

Cited by 16 publications

References 3 publications

The role of the circle of Willis in internal carotid artery stenosis and anatomical variations: a computational study based on a patient-specific three-dimensional model

The role of the circle of Willis in internal carotid artery stenosis and anatomical variations: a computational study based on a patient-specific three-dimensional model

State-of-the-Art Computational Models of Circle of Willis With Physiological Applications: A Review

The circle of Willis revisited: Forebrain dehydration sensing facilitated by the anterior communicating artery

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