Comparison of Newtonian and Non-newtonian Fluid Models in Blood Flow Simulation in Patients With Intracranial Arterial Stenosis

Haipeng Liu, Linfang Lan, Jill Abrigo, Hing Lung Ip, Yannie O.Y. Soo, Dingchang Zheng, Ka Sing Wong, Defeng Wang, Lin Shi, Thomas Wai Hong Leung, Xinyi Leng

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    Background: Newtonian fluid model has been commonly applied in simulating cerebral blood flow in intracranial atherosclerotic stenosis (ICAS) cases using computational fluid dynamics (CFD) modeling, while blood is a shear-thinning non-Newtonian fluid. We aimed to investigate the differences of cerebral hemodynamic metrics quantified in CFD models built with Newtonian and non-Newtonian fluid assumptions, in patients with ICAS.

    Methods: We built a virtual artery model with an eccentric 75% stenosis and performed static CFD simulation. We also constructed CFD models in three patients with ICAS of different severities in the luminal stenosis. We performed static simulations on these models with Newtonian and two non-Newtonian (Casson and Carreau-Yasuda) fluid models. We also performed transient simulations on another patient-specific model. We measured translesional pressure ratio (PR) and wall shear stress (WSS) values in all CFD models, to reflect the changes in pressure and WSS across a stenotic lesion. In all the simulations, we compared the PR and WSS values in CFD models derived with Newtonian, Casson, and Carreau-Yasuda fluid assumptions.

    Results: In all the static and transient simulations, the Newtonian/non-Newtonian difference on PR value was negligible. As to WSS, in static models (virtual and patient-specific), the rheological difference was not obvious in areas with high WSS, but observable in low WSS areas. In the transient model, the rheological difference of WSS areas with low WSS was enhanced, especially during diastolic period.

    Conclusion: Newtonian fluid model could be applicable for PR calculation, but caution needs to be taken when using the Newtonian assumption in simulating WSS especially in severe ICAS cases.
    Original languageEnglish
    Article number718540
    Number of pages11
    JournalFrontiers in Physiology
    Early online date6 Sept 2021
    Publication statusPublished - 6 Sept 2021

    Bibliographical note

    This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.


    General Research Fund (Reference No. 14106019), Research Grants Council of Hong Kong; the Lee Hysan Postdoctoral Fellowship in Clinical Neurosciences, the Chinese University of Hong Kong; and the Young Scientists Fund (Reference No. 81601000)


    • non-Newtonian fluid
    • intracranial atherosclerotic stenosis
    • , computational fluid dynamics
    • translesional pressure ratio
    • wall shear stress
    • computational fluid dynamics

    ASJC Scopus subject areas

    • Physiology (medical)
    • Physiology


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