Artery Length Sensitivity in Patient-Specific Cerebral Aneurysm Simulations

Hodis, Simona; Kargar, Saeed; Kallmes, David F.; Dragomir-Daescu, Dan

doi:10.3174/ajnr.a4179

Cited by 18 publications

(14 citation statements)

References 21 publications

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“…The results of this study suggest that the location of the upstream boundary should not be placed just after the bifurcation. As for a bend, Hodis et al showed that a bend in the ICA renders a prominent difference in the results of the CFD, including velocities, WSS, and OSI inside a cerebral aneurysm (Hodis et al, 2015). However, in the present study, the relatively small difference between Models A and C implies that the assumption of a uniform velocity profile just after the bend has a small influence on the blood flow inside the aneurysm.…”

contrasting

confidence: 53%

Effects of upstream bifurcation and bend on the blood flow in a cerebral aneurysm

Suzuki

Funamoto

Sugiyama

et al. 2017

JBSE

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Mechanisms of development, growth, and rupture of a cerebral aneurysm have been studied by computational fluid dynamics (CFD), calculating hemodynamic parameters, such as wall shear stress, oscillatory shear index (OSI), and relative residence time (RRT). It is well known that the upstream velocity profile and upstream vessel shape influence the computational results. However, few studies have dealt with cases involving a bifurcation upstream of a cerebral aneurysm. Furthermore, the fluid-dynamic effects of multiple structural elements of upstream vessel shape, such as a bifurcation and a bend, on the results of CFD remain unknown. The purpose of this study was to elucidate the fluid-dynamic effects of multiple structural elements of upstream vessel shape such as bifurcation and bend on blood flow and hemodynamic parameters inside an aneurysm. Computations were performed for blood flow in a cerebral aneurysm with upstream sequential elements of a bifurcation, a bend, and a straight section, using four models with different upstream boundaries, i.e., before the bifurcation, after the bifurcation before the bend, after the bend, and after the straight section just before the cerebral aneurysm. The results were compared to elucidate the effect of each upstream structural element on the blood flow and hemodynamic parameters in the cerebral aneurysm. Differences in OSI and RRT resulting from changes in the velocity distribution were observed locally in the aneurysm between the models. It was also found that the effect of the bifurcation on the velocity distribution was greater than that of the bend.

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contrasting

confidence: 53%

Effects of upstream bifurcation and bend on the blood flow in a cerebral aneurysm

Suzuki

Funamoto

Sugiyama

et al. 2017

JBSE

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“…The differences we report in hemodynamic indices due to outflow strategy, as shown in Fig 3, are comparable with those reported due to CFD solution strategy, 2 which were, in turn, far greater than those due to non-Newtonian viscosity. 21 Similarly, the divergent conclusions of Ramalho et al 16 and Venugopal et al 17 were drawn from TAWSS patterns that appear, qualitatively at least, to be comparable with those presented in studies of geometric [22][23][24] or inflow 3 uncertainties. Together these suggest that the outflow strategy should be considered at least as important as other assumptions or uncertainties in aneurysm CFD.…”

Section: Relationship To Previous Studies: Impact Of Outflow or Not?mentioning

confidence: 87%

Better Than Nothing: A Rational Approach for Minimizing the Impact of Outflow Strategy on Cerebrovascular Simulations

Chnafa

Brina

Pereira

et al. 2017

AJNR Am J Neuroradiol

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“…Original stereolithography geometries were obtained from AneuriskWeb repository and edited for smoothness and branch elongations in Autodesk Meshmixer. Only models with long enough (at least 10 times the arterial diameter) original inlet branches were included in the current study to minimize the effect of nonphysiological boundary conditions . Some outlets were artificially extended downstream from the aneurysm dome or bifurcations to prevent boundary effects.…”

Section: Methodsmentioning

confidence: 99%

“…Only models with long enough (at least 10 times the arterial diameter) original inlet branches were included in the current study to minimize the effect of nonphysiological boundary conditions. 25,26 Some outlets were artificially extended downstream from the aneurysm dome or bifurcations to prevent boundary effects. For the purpose of capturing flow patterns independent of mesh element size, we generated uniform hexahedral dominant meshes with the element size of 0.08 mm, which was the smallest mesh resolution used in a comprehensive grid convergence study of Hodis et al 27 Computational meshes were generated using SnappyHexMesh from OpenFOAM.…”

Section: Patient-specific Simulations 221 Preprocessingmentioning

confidence: 99%

Correlation of flow complexity parameter with aneurysm rupture status

Hodis

2018

Numer Methods Biomed Eng

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Ruptured aneurysms are known to have complex flow patterns and concentrated inflow jet, but a quantifiable measure for the degree of flow complexity in patient-specific geometries has not been established. Previously, we proposed a flow complexity parameter that provides a quantitative description of the complexity of flow patterns through calculated curvature and torsion of the flow field. The purpose of the current study was to provide an analytic solution of the flow complexity parameter and assess a possible correlation with the rupture status of cerebral aneurysms by analyzing the parameter on five ruptured and five unruptured aneurysms from anterior communicating artery. We analyzed the flow complexity parameter in jet and non-jet regions in order to measure the concentration of the jet flow and the complexity of the non-jet flow. We found that on average, in a ruptured case the jet region is significantly less complex (4.5 times) than the jet region in an unruptured case, while the non-jet region is significantly more complex (3.5 times) than the non-jet region in an unruptured case. We also found a strong positive correlation of the non-jet complexity with dome volume in ruptured cases, but no correlation of jet complexity with dome volume. These findings suggest that a ruptured aneurysm has more than 4 times more concentrated inflow jet and more than 3 times more complex flow patterns in non-jet region than an unruptured aneurysm. This newly implemented kinematic parameter provides a measurable degree of complexity of flow patterns in cerebral aneurysms that can better assess aneurysm rupture risk.

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Artery Length Sensitivity in Patient-Specific Cerebral Aneurysm Simulations

Abstract: BACKGROUND AND PURPOSE:The reconstruction of aneurysm geometry is a main factor affecting the accuracy of hemodynamics simulations in patient-specific aneurysms. We analyzed the effects of the inlet artery length on intra-aneurysmal flow estimations by using 10 ophthalmic aneurysm models.

Cited by 18 publications

References 21 publications

Effects of upstream bifurcation and bend on the blood flow in a cerebral aneurysm

Effects of upstream bifurcation and bend on the blood flow in a cerebral aneurysm

Better Than Nothing: A Rational Approach for Minimizing the Impact of Outflow Strategy on Cerebrovascular Simulations

Correlation of flow complexity parameter with aneurysm rupture status

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