Quantifying the Large-Scale Hemodynamics of Intracranial Aneurysms

Byrne, Greg; Mut, Fernando; Cebral, Juan R.

doi:10.3174/ajnr.a3678

Cited by 91 publications

(86 citation statements)

References 25 publications

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“…Interface 14: 20170021 in vortex core lines, vVF and sVF. Consistent with previous computational studies [18], we found that core line lengths are dynamic and change between 33 and 56% throughout the cardiac cycle (see electronic supplementary material, figure S1). Additionally, we confirmed that maximum Q occurs at peak systole (see electronic supplementary material, figure S2).…”

Section: Sensitivity Analysissupporting

confidence: 91%

Identification of vortex structures in a cohort of 204 intracranial aneurysms

Varble

Trylesinski

Xiang

et al. 2017

J. R. Soc. Interface.

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An intracranial aneurysm (IA) is a cerebrovascular pathology that can lead to death or disability if ruptured. Abnormal wall shear stress (WSS) has been associated with IA growth and rupture, but little is known about the underlying flow physics related to rupture-prone IAs. Previous studies, based on analysis of a few aneurysms or partial views of three-dimensional vortex structures, suggest that rupture is associated with complex vortical flow inside IAs. To further elucidate the relevance of vortical flow in aneurysm pathophysiology, we studied 204 patient IAs (56 ruptured and 148 unruptured). Using objective quantities to identify three-dimensional vortex structures, we investigated the characteristics associated with aneurysm rupture and if these features correlate with previously proposed WSS and morphological characteristics indicative of IA rupture. Based on the Q-criterion definition of a vortex, we quantified the degree of the aneurysmal region occupied by vortex structures using the volume vortex fraction (vVF) and the surface vortex fraction (sVF). Computational fluid dynamics simulations showed that the sVF, but not the vVF, discriminated ruptured from unruptured aneurysms. Furthermore, we found that the near-wall vortex structures co-localized with regions of inflow jet breakdown, and significantly correlated to previously proposed haemodynamic and morphologic characteristics of ruptured IAs.

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Section: Sensitivity Analysissupporting

confidence: 91%

Identification of vortex structures in a cohort of 204 intracranial aneurysms

Varble

Trylesinski

Xiang

et al. 2017

J. R. Soc. Interface.

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show abstract

“…These data indicate that previous findings on vortex instability by using generalized inflow boundary conditions should be considered with caution. 38 Both patient-specific and generalized inflow boundary conditions are traditionally used for CFD analysis of cerebral aneurysm hemodynamics. However, only 2 authors have so far compared both approaches.…”

Section: Discussionmentioning

confidence: 99%

Generalized versus Patient-Specific Inflow Boundary Conditions in Computational Fluid Dynamics Simulations of Cerebral Aneurysmal Hemodynamics

Jansen¹,

Schneiders²,

Potters³

et al. 2014

American Journal of Neuroradiology

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BACKGROUND AND PURPOSE:Attempts have been made to associate intracranial aneurysmal hemodynamics with aneurysm growth and rupture status. Hemodynamics in aneurysms is traditionally determined with computational fluid dynamics by using generalized inflow boundary conditions in a parent artery. Recently, patient-specific inflow boundary conditions are being implemented more frequently. Our purpose was to compare intracranial aneurysm hemodynamics based on generalized versus patient-specific inflow boundary conditions.

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“…Our study concerns itself with a type of flow dynamics-based instability. In a number of CFD studies in the past, a connection between complex and unstable flow patterns and ruptured aneurysms has been observed, and there has been evidence that unstable flow, manifested in multiple or time-varying vortices, is associated with ruptured aneurysms [6,[36][37][38][39]. Therefore, it is reasonable to investigate whether the persistent flow fluctuations emerging under a steady inlet boundary condition could be associated with rupture.…”

Section: Discussionmentioning

confidence: 99%

Flow Instability Detected by High-Resolution Computational Fluid Dynamics in Fifty-Six Middle Cerebral Artery Aneurysms

Varble

Xiang

Lin

et al. 2016

Journal of Biomechanical Engineering

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Recent high-resolution computational fluid dynamics (CFD) studies have detected persistent flow instability in intracranial aneurysms (IAs) that was not observed in previous in silico studies. These flow fluctuations have shown incidental association with rupture in a small aneurysm dataset. The aims of this study are to explore the capabilities and limitations of a commercial CFD solver in capturing such velocity fluctuations, whether fluctuation kinetic energy (fKE) as a marker to quantify such instability could be a potential parameter to predict aneurysm rupture, and what geometric parameters might be associated with such fluctuations. First, we confirmed that the second-order discretization schemes and high spatial and temporal resolutions are required to capture these aneurysmal flow fluctuations. Next, we analyzed 56 patient-specific middle cerebral artery (MCA) aneurysms (12 ruptured) by transient, high-resolution CFD simulations with a cycle-averaged, constant inflow boundary condition. Finally, to explore the mechanism by which such flow instabilities might arise, we investigated correlations between fKE and several aneurysm geometrical parameters. Our results show that flow instabilities were present in 8 of 56 MCA aneurysms, all of which were unruptured bifurcation aneurysms. Statistical analysis revealed that fKE could not differentiate ruptured from unruptured aneurysms. Thus, our study does not lend support to these flow instabilities (based on a cycle-averaged constant inflow as opposed to peak velocity) being a marker for rupture. We found a positive correlation between fKE and aneurysm size as well as size ratio. This suggests that the intrinsic flow instability may be associated with the breakdown of an inflow jet penetrating the aneurysm space.

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Quantifying the Large-Scale Hemodynamics of Intracranial Aneurysms

Cited by 91 publications

References 25 publications

Identification of vortex structures in a cohort of 204 intracranial aneurysms

Identification of vortex structures in a cohort of 204 intracranial aneurysms

Generalized versus Patient-Specific Inflow Boundary Conditions in Computational Fluid Dynamics Simulations of Cerebral Aneurysmal Hemodynamics

Flow Instability Detected by High-Resolution Computational Fluid Dynamics in Fifty-Six Middle Cerebral Artery Aneurysms

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