Variability of hemodynamic parameters using the common viscosity assumption in a computational fluid dynamics analysis of intracranial aneurysms

Suzuki, Takashi; Takao, Hiroyuki; Suzuki, Takamasa; Suzuki, Tomoaki; Masuda, Shunsuke; Dahmani, Chihebeddine; Watanabe, Manabu; Mamori, Hiroya; Ishibashi, Toshiyuki; Yamamoto, Hideki; Yamamoto, Makoto; Murayama, Yuichi

doi:10.3233/thc-161245

Cited by 22 publications

(10 citation statements)

References 27 publications

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“…They concluded that adopting a non-Newtonian viscosity model highlighted the hemodynamic differences induced by the presence of a bleb and improved the discriminant statistics in rupture prediction. Suzuki et al 36 first compared the CFD simulation results of the Newtonian viscosity model with those of actual viscosity data obtained from blood sample data of healthy volunteers. They concluded that CFD using either the common Newtonian or non-Newtonian viscosity assumption could lead to values different from those of the patient-specific viscosity model for hemodynamic parameters such as WSS.…”

Section: Limitations Of Cfd Studiesmentioning

confidence: 99%

Computational fluid dynamics as a risk assessment tool for aneurysm rupture

Murayama

Fujimura

Suzuki

et al. 2019

Neurosurgical Focus

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OBJECTIVEThe authors reviewed the clinical role of computational fluid dynamics (CFD) in assessing the risk of intracranial aneurysm rupture.METHODSA literature review was performed to identify reports on CFD assessment of aneurysms using PubMed. The usefulness of various hemodynamic parameters, such as wall shear stress (WSS) and the Oscillatory Shear Index (OSI), and their role in aneurysm rupture risk analysis, were analyzed.RESULTSThe authors identified a total of 258 published articles evaluating rupture risk, growth, and endovascular device assessment. Of these 258 articles, 113 matching for CFD and hemodynamic parameters that contribute to the risk of rupture (such as WSS and OSI) were identified. However, due to a lack of standardized methodology, controversy remains on each parameter’s role.CONCLUSIONSAlthough controversy continues to exist on which risk factors contribute to predict aneurysm rupture, CFD can provide additional parameters to assess this rupture risk. This technology can contribute to clinical decision-making or evaluation of efficacy for endovascular methods and devices.

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Section: Limitations Of Cfd Studiesmentioning

confidence: 99%

Computational fluid dynamics as a risk assessment tool for aneurysm rupture

Murayama

Fujimura

Suzuki

et al. 2019

Neurosurgical Focus

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“…[54][55][56] For this purpose, CFD simulations should account for the sensitive values of WSS, as indicated by the results of Zhou et al 15 Different non-Newtonian models produce deviations from the Newtonian assumption within similar ranges to the MKM. 4 However, due to the empirical nature of the non-Newtonian model, they are not consistent and sometimes they produce higher WSS (i.e. less sensitive results).…”

Section: Wall Shear Stressmentioning

confidence: 99%

“…Recent literature shows considerable differences in CA wall shear stress (WSS) between Newtonian and non-Newtonian models. [4][5][6] Each and every non-Newtonian model has different underlying physics. 7 However, the majority of such models are empirical correlations which represent blood as shear-thinning fluid regardless of its components.…”

Section: Introductionmentioning

confidence: 99%

Computational fluid dynamics simulations of cerebral aneurysm using Newtonian, power-law and quasi-mechanistic blood viscosity models

Saqr

2020

Proc Inst Mech Eng H

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Cerebral aneurysm is a fatal neurovascular disorder. Computational fluid dynamics simulation of aneurysm haemodynamics is one of the most important research tools which provide increasing potential for clinical applications. However, computational fluid dynamics modelling of such delicate neurovascular disorder involves physical complexities that cannot be easily simplified. Recently, it was shown that the Newtonian simplification used to close the shear stress tensor of the Navier–Stokes equation is not sufficient to explore aneurysm haemodynamics. This article explores the differences between the latter simplification, non-Newtonian power-law model and a newly proposed quasi-mechanistic model. The modified Krieger model, which treats blood as a suspension of plasma and particles, was implemented in computational fluid dynamics context here for the first time and is made available to the readers in a C# code in the supplementary material of this article. Two middle-cerebral artery and two anterior-communicating artery aneurysms, all ruptured, were utilized here as case studies. It was shown that the modified Krieger model had higher sensitivity for wall shear stress calculations in comparison with the other two models. The modified Krieger model yielded lower wall shear stress values consistently in comparison with the other two models. Moreover, the modified Krieger model has generally predicted higher pressure in the aneurysm models. Based on published aneurysm rupture studies, it is believed that ruptured aneurysms are usually correlated with lower wall shear stress values than unruptured ones. Therefore, this work concludes that the modified Krieger model is a potential candidate for providing better clinical relevance to aneurysm computational fluid dynamics simulations.

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“…Xiang et al 19) reported a reduction in WSS at the aneurysmal bleb by CFD analysis with Casson's model in comparison with the Newtonian model, suggesting that the risk of aneurysmal rupture may be underestimated by Newtonian model calculation. Suzuki et al 20) applied two models, Casson's and Newtonian models, which differ in viscosity, for CFD analysis of unruptured cerebral aneurysms, and reported that the normalized WSS was reduced by 25% at maximum in Casson's model, suggesting the influence of viscosity on CFD analysis. In this study, we prepared Casson's model from the average shear rate-blood viscosity curve based on the actual values of 50 healthy adults, and applied it for CFD analysis for the first time.…”

Section: Cfd Analysis Using Casson's Modelmentioning

confidence: 99%

Hemodynamic Assessment of Cerebral Aneurysms Using Computational Fluid Dynamics (CFD) Involving the Establishment of Non-Newtonian Fluid Properties

Tanaka

Ishida

Kawamura

et al. 2018

JNET

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The hemodynamics of cerebral aneurysms was evaluated by computational fluid dynamics (CFD) analysis using the non-Newtonian (Casson's) fluid model and the Newtonian fluid model obtained from measurements. The two fluid models were examined to clarify the influence of blood viscosity on hemodynamic parameters. Methods: We measured blood viscosity of blood obtained from 50 healthy adults at 12 shear rate ranges using a compact-sized falling needle rheometer. Blood viscosity was set as the Newtonian and Casson's fluid models determined using these measurements. In all, 12 cerebral aneurysms were evaluated by transient analysis to calculate the wall shear stress (WSS), wall shear stress gradient (WSSG), flow velocity (FV), oscillatory shear index (OSI), and parameters that facilitate the quantitative assessment of the fluctuations of individual vectors, including the gradient oscillatory number (GON) and oscillatory velocity index (OVI). Bland-Altman analysis was performed to compare the two models, and systematic errors were examined. Results: The relationship between the apparent viscosity and the shear rate obtained from blood samples of 50 healthy adults revealed the characteristics of Casson's fluid. The systematic errors in hemodynamic parameters for the two fluid models were small, and the correlation coefficients of the WSS, WSSG, FV, OSI, GON, and OVI were 0.9999, 0.9999, 0.9985, 0.9734, 0.9758, and 0.9258, respectively. Furthermore, the means of these hemodynamic parameters for the entire aneurysm showed a high consistency rate between the two groups, whereas different values were observed in focal hemodynamics including blebs. Conclusion: Newtonian fluid numerical modeling may be useful for analyzing the entire aneurysm. On the other hand, these results indicated that hemodynamics analyzed using non-Newtonian blood viscosity could have certain effects on focal hemodynamics that may be related to aneurysm growth and rupture.

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Variability of hemodynamic parameters using the common viscosity assumption in a computational fluid dynamics analysis of intracranial aneurysms

Cited by 22 publications

References 27 publications

Computational fluid dynamics as a risk assessment tool for aneurysm rupture

Computational fluid dynamics as a risk assessment tool for aneurysm rupture

Computational fluid dynamics simulations of cerebral aneurysm using Newtonian, power-law and quasi-mechanistic blood viscosity models

Hemodynamic Assessment of Cerebral Aneurysms Using Computational Fluid Dynamics (CFD) Involving the Establishment of Non-Newtonian Fluid Properties

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