Suitability of lattice Boltzmann inlet and outlet boundary conditions for simulating flow in image‐derived vasculature

Feiger, Bradley; Vardhan, Madhurima; Gounley, John; Mortensen, Matthew; Nair, Priya; Chaudhury, Rafeed; Randles, Amanda

doi:10.1002/cnm.3198

Cited by 22 publications

(9 citation statements)

References 57 publications

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“…Regarding the spatial profile, we use the quadratic form pertaining to Poiseuille flow: which is valid if the flow is quasi-static and laminar. It can be applied to boundary planes which are circular, where becomes a parabola, as well as those of irregular shapes 43 . Regarding the temporal profile, we impose a sinusoidal wave of frequency on top of a mean flow such that .…”

Section: Methodsmentioning

confidence: 99%

Parametric analysis of an efficient boundary condition to control outlet flow rates in large arterial networks

McCullough

Coveney

2022

Sci Rep

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Substantial effort is being invested in the creation of a virtual human—a model which will improve our understanding of human physiology and diseases and assist clinicians in the design of personalised medical treatments. A central challenge of achieving blood flow simulations at full-human scale is the development of an efficient and accurate approach to imposing boundary conditions on many outlets. A previous study proposed an efficient method for implementing the two-element Windkessel model to control the flow rate ratios at outlets. Here we clarify the general role of the resistance and capacitance in this approach and conduct a parametric sweep to examine how to choose their values for complex geometries. We show that the error of the flow rate ratios decreases exponentially as the resistance increases. The errors fall below 4% in a simple five-outlets model and 7% in a human artery model comprising ten outlets. Moreover, the flow rate ratios converge faster and suffer from weaker fluctuations as the capacitance decreases. Our findings also establish constraints on the parameters controlling the numerical stability of the simulations. The findings from this work are directly applicable to larger and more complex vascular domains encountered at full-human scale.

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Section: Methodsmentioning

confidence: 99%

Parametric analysis of an efficient boundary condition to control outlet flow rates in large arterial networks

McCullough

Coveney

2022

Sci Rep

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“…Table 5 shows the outlet diameter and resting resistance at each outlet for a patient's left coronary artery with different outlet truncation strategies. For all the 68 vessels, the outlet diameter and resistance of (i) Strategy_1 were 1.75 ± 0.45 mm and 16.88 ± 6.61 dyn⋅s/cm 5 , respectively, and (ii) 1.93 ± 0.41 mm and 14.45 ±…”

Section: Impact Of Outlet Truncation Position On Ffrctmentioning

confidence: 97%

“…This is because the BCs are physiologically and mathematically relevant, as the physiological state of the outlet distal vasculature governs its mathematical BC model 1 . Different physiological states correspond to different mathematical models, while a particular outlet BC corresponds to a specific solution of flow pattern and pressure field distribution in the simulated coronary artery 5 . Therefore, in order to accurately determine FFRCT for valid clinical decision‐making, the setting of the outlet BC should be patient‐specific or personalized, and follow the patient's real physiological state.…”

Section: Introductionmentioning

confidence: 99%

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Physiologically personalized coronary blood flow model to improve the estimation of noninvasive fractional flow reserve

Liu

Rao

et al. 2021

Medical Physics

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Purpose Coronary outlet resistance is influenced by the quantification and distribution of resting coronary blood flow. It is crucial for a more physiologically accurate estimation of fractional flow reserve (FFR) derived from computed tomography angiography (CTA), referred to as FFRCT. This study presents a physiologically personalized (PP)‐based coronary blood flow model involving the outlet boundary condition (BC) and a standardized outlet truncation strategy to estimate the outlet resistance and FFRCT. Methods In this study, a total of 274 vessels were retrospectively collected from 221 patients who underwent coronary CTA and invasive FFR within 14 days. For FFRCT determination, we have employed a PP‐based outlet BC model involving personalized physiological parameters and left ventricular mass (LVM) to quantify resting coronary blood flow. We evaluated the improvement achieved in the diagnostic performance of FFRCT by using the PP‐based outlet BC model relative to the LVM‐based model, with respect to the invasive FFR. Additionally, in order to evaluate the impact of the outlet truncation strategy on FFRCT, 68 vessels were randomly selected and analyzed independently by two operators, by using two different outlet truncation strategies at 1‐month intervals. Results The per‐vessel diagnostic performance of the PP‐based outlet BC model was improved, based on invasive FFR as reference, compared to the LVM‐based model: (i) accuracy/sensitivity/specificity: 91.2%/90.4%/91.8% versus 86.5%/84.6%/87.6%, for the entire dataset of 274 vessels, (ii) accuracy/sensitivity/specificity: 88.7%/82.4%/90.4% versus 82.4%/ 76.5%/84.0%, for moderately stenosis lesions. The standardized outlet truncation strategy showed good repeatability with the Kappa coefficient of 0.908. Conclusions It has been shown that our PP‐based outlet BC model and standardized outlet truncation strategy can improve the diagnostic performance and repeatability of FFRCT.

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“…Surely, the proper adoption of BC is a key determinant for the stability, efficiency and accuracy of simulations. Previous studies summarize a variety of these conditions (Feiger et al, 2019;Hu et al, 2017;Rosis et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Lattice-Boltzmann simulation of incompressible fluid flow past immersed bodies: models and boundary conditions

Krenchiglova

Santos

Siebert

et al. 2022

HFF

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Purpose The main purpose of this paper was to investigate Lattice Boltzmann (LB) models for the bulk incompressible flow past immersed bodies and to find the set of boundary conditions (BCs) that can be considered suitable for modeling the borders of the numerical simulation domain in such a way as to avoid any effect of these BC on the flow trail that is formed behind the body. Design/methodology/approach Three different models of the Lattice Boltzmann equation (LBE) and six different sets of BCs are tested. In addition to the classical LBE based on the Bhatnagar–Gross–Krook (BGK) single relaxation time collision model, a moments-based model and a model with two relaxation times were investigated. Findings The flow pattern and its macroscopic effects on the aerodynamic coefficients appear to be very dependent on the set of BC models used for the borders of the numerical domain. The imposition of pressure at the exit results in pressure perturbations, giving rise to sound waves that propagate back into the simulation domain, producing perturbations on the upwind flow. In the same way, the free-slip BC for the lateral bords appears to affect the trail of vortices behind the body in this range of Reynolds number (Re = 1,000). Originality/value The paper investigates incompressible flow past immersed bodies and presents the set of BCs that can be considered suitable for modeling the borders of the numerical simulation domain in such a way as to avoid any effect of these BCs on the flow trail that is formed behind the body.

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Suitability of lattice Boltzmann inlet and outlet boundary conditions for simulating flow in image‐derived vasculature

Cited by 22 publications

References 57 publications

Parametric analysis of an efficient boundary condition to control outlet flow rates in large arterial networks

Parametric analysis of an efficient boundary condition to control outlet flow rates in large arterial networks

Physiologically personalized coronary blood flow model to improve the estimation of noninvasive fractional flow reserve

Lattice-Boltzmann simulation of incompressible fluid flow past immersed bodies: models and boundary conditions

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