Effects of Non-Newtonian Viscosity on the Hemodynamics of Cerebral Aneurysms

Gibaly, Ahmed el; El-Bassiouny, Omar A.; Diaa, Omar; Shehata, Ali I.; Hassan, Tamer; Saqr, Khalid M.

doi:10.4028/www.scientific.net/amm.819.366

Cited by 7 publications

(3 citation statements)

References 17 publications

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“…Low WSS values on the aneurysm wall are known to be an important rupture risk factor, and severe gradients do contribute to the aneurysm growth via a pathological route. 34 The influence of antiplatelet therapy on the viscosity of blood will be taken into consideration in our future study. Several limitations in this study should be noted.…”

Section: Discussionmentioning

confidence: 99%

Hemodynamic effects of intracranial aneurysms from stent-induced straightening of parent vessels by stent-assisted coiling embolization

Leng

Wan

Li³

et al. 2021

Interv Neuroradiol

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Background Straightening of parent vessels happens for stent-assisted coiling embolization (SACE) treatment of intracranial aneurysms. This study aims to investigate aneurysmal hemodynamic modifications caused by stent-induced vessel straightening. Methods Stent and coil deployments of a SACE-treated distal bifurcation aneurysm by finite element method were performed first with the preoperative (not straightened, NS) and postoperative (straightened, S) vessel models respectively. Computational fluid dynamics were then performed for eight models, including (I) NS only model, (II) NS+stent model, (III) NS+coils model, (IV) NS+stent+coils model, (V) S only model, (VI) S+stent model, (VII) S+coils model, and (VIII) S+stent+coils model. Finally, changes in aneurysmal flow velocity, isovelocity surface and wall shear stress (WSS) were analyzed qualitatively and quantitatively. Results The flow was less in the S models than that in the corresponding NS models. Coils blocked most of the flow into the aneurysm sac in both NS models and S models and vessel straightening had more profound effect on the high aneurysmal flow volume reduction than coiling, while stenting generated adverse effect on flow reduction. Taking the NS only model as baseline (100%), the sac-averaged velocities of models II to VIII were 112%, 36%, 42%, 45%, 39%, 12%, 13%, and high flow volumes were 119%, 21%, 30%, 10%, 8%, 3%, 3%, while the sac-averaged WSSs were 106%, 37%, 44%, 41%, 35%, 17% and 24%, respectively. Conclusions Stent-induced vessel straightening combined coil embolization has the best performance in hemodynamic modifications and may reduce the recurrence rate, whereas stenting may generate adverse effect on hemodynamic alterations.

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Section: Discussionmentioning

confidence: 99%

Hemodynamic effects of intracranial aneurysms from stent-induced straightening of parent vessels by stent-assisted coiling embolization

Leng

Wan

Li³

et al. 2021

Interv Neuroradiol

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“…To clarify whether the assumption of a constant viscosity is valid for the continuity approach, several experimental and numerical investigations were conducted. While some groups argue that significant differences between both assumptions exist, 22,25 others demonstrated that the non-Newtonian effects are negligible or have just a secondary impact. 42,48…”

Section: Blood Treatmentmentioning

confidence: 99%

A review on the reliability of hemodynamic modeling in intracranial aneurysms: why computational fluid dynamics alone cannot solve the equation

Berg

Saalfeld²,

Voß

et al. 2019

Neurosurgical Focus

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Computational blood flow modeling in intracranial aneurysms (IAs) has enormous potential for the assessment of highly resolved hemodynamics and derived wall stresses. This results in an improved knowledge in important research fields, such as rupture risk assessment and treatment optimization. However, due to the requirement of assumptions and simplifications, its applicability in a clinical context remains limited.This review article focuses on the main aspects along the interdisciplinary modeling chain and highlights the circumstance that computational fluid dynamics (CFD) simulations are embedded in a multiprocess workflow. These aspects include imaging-related steps, the setup of realistic hemodynamic simulations, and the analysis of multidimensional computational results. To condense the broad knowledge, specific recommendations are provided at the end of each subsection.Overall, various individual substudies exist in the literature that have evaluated relevant technical aspects. In this regard, the importance of precise vessel segmentations for the simulation outcome is emphasized. Furthermore, the accuracy of the computational model strongly depends on the specific research question. Additionally, standardization in the context of flow analysis is required to enable an objective comparison of research findings and to avoid confusion within the medical community. Finally, uncertainty quantification and validation studies should always accompany numerical investigations.In conclusion, this review aims for an improved awareness among physicians regarding potential sources of error in hemodynamic modeling for IAs. Although CFD is a powerful methodology, it cannot provide reliable information, if pre- and postsimulation steps are inaccurately carried out. From this, future studies can be critically evaluated and real benefits can be differentiated from results that have been acquired based on technically inaccurate procedures.

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“…On the other hand, for real-world problems, the advantage of considering the more general fluids of power-law type is not slight. In effect, as [35] describes, practitioners employed them to investigate problems in chemical engineering of colloids, suspensions, and polymeric fluids, see [49,48,52,4,9,41,44], in ice mechanics and glaciology, see [37,53,25], in blood-rheology, see [8,7,10,14,15,39,47,17], and also in geology, see [36], to name a few instances.…”

mentioning

confidence: 99%

Local null controllability of a class of non-Newtonian incompressible viscous fluids

Carvalho

Límaco

Menezes

et al. 2022

EECT

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<p style='text-indent:20px;'>We investigate the null controllability property of systems that mathematically describe the dynamics of some non-Newtonian incompressible viscous flows. The principal model we study was proposed by O. A. Ladyzhenskaya, although the techniques we develop here apply to other fluids having a shear-dependent viscosity. Taking advantage of the Pontryagin Minimum Principle, we utilize a bootstrapping argument to prove that sufficiently smooth controls to the forced linearized Stokes problem exist, as long as the initial data in turn has enough regularity. From there, we extend the result to the nonlinear problem. As a byproduct, we devise a quasi-Newton algorithm to compute the states and a control, which we prove to converge in an appropriate sense. We finish the work with some numerical experiments.</p>

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Effects of Non-Newtonian Viscosity on the Hemodynamics of Cerebral Aneurysms

Cited by 7 publications

References 17 publications

Hemodynamic effects of intracranial aneurysms from stent-induced straightening of parent vessels by stent-assisted coiling embolization

Hemodynamic effects of intracranial aneurysms from stent-induced straightening of parent vessels by stent-assisted coiling embolization

A review on the reliability of hemodynamic modeling in intracranial aneurysms: why computational fluid dynamics alone cannot solve the equation

Local null controllability of a class of non-Newtonian incompressible viscous fluids

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