Comparison of Hemodynamic Visualization in Cerebral Arteries: Can Magnetic Resonance Imaging Replace Computational Fluid Dynamics?

Ngo, Minh Tri; Lee, Ui Yun; Ha, Hojin; Jin, Ning; Chung, Gyung Ho; Kwak, Yeong Gon; Jung, Ju Yeon; Kwak, Hyo Sung

doi:10.3390/jpm11040253

Cited by 9 publications

(3 citation statements)

References 42 publications

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“…However, similar to previous studies [21][22][23][24], our results of 4D flow MRI with ITK-SNAP analysis still tend to measure lower flow velocities than CFD in several subjects (Figure 3b). This is due to the deviation in the geometric angiographic reconstruction between the two methods.…”

Section: Discussionsupporting

confidence: 91%

Improving Blood Flow Visualization of Recirculation Regions at Carotid Bulb in 4D Flow MRI Using Semi-Automatic Segmentation with ITK-SNAP

Ngo

Lee

et al. 2021

Diagnostics

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Assessment of carotid bulb hemodynamics using four-dimensional (4D) flow magnetic resonance imaging (MRI) requires accurate segmentation of recirculation regions that is frequently hampered by limited resolution. This study aims to improve the accuracy of 4D flow MRI carotid bulb segmentation and subsequent recirculation regions analysis. Time-of-flight (TOF) MRI and 4D flow MRI were performed on bilateral carotid artery bifurcations in seven healthy volunteers. TOF-MRI data was segmented into 3D geometry for computational fluid dynamics (CFD) simulations. ITK-SNAP segmentation software was included in the workflow for the semi-automatic generation of 4D flow MRI angiographic data. This study compared the velocities calculated at the carotid bifurcations and the 3D blood flow visualization at the carotid bulbs obtained by 4D flow MRI and CFD. By applying ITK-SNAP segmentation software, an obvious improvement in the 4D flow MRI visualization of the recirculation regions was observed. The 4D flow MRI images of the recirculation flow characteristics of the carotid artery bulbs coincided with the CFD. A reasonable agreement was found in terms of velocity calculated at the carotid bifurcation between CFD and 4D flow MRI. However, the dispersion of velocity data points relative to the local errors of measurement in 4D flow MRI remains. Our proposed strategy showed the feasibility of improving recirculation regions segmentation and the potential for reliable blood flow visualization in 4D flow MRI. However, quantitative analysis of recirculation regions in 4D flow MRI with ITK-SNAP should be enhanced for use in clinical situations.

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Section: Discussionsupporting

confidence: 91%

Improving Blood Flow Visualization of Recirculation Regions at Carotid Bulb in 4D Flow MRI Using Semi-Automatic Segmentation with ITK-SNAP

Ngo

Lee

et al. 2021

Diagnostics

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“…It has been argued that growth and rupture of an aneurysm are generated by a three-way relationship among the pathobiology of the wall, aneurysmal geometry, and intra-aneurysmal flow [3,4]. To quantify the hemodynamics of cerebral aneurysms, phase-contrast magnetic resonance imaging (MRI), also termed four-dimensional (4D) flow MRI, and computational fluid dynamics (CFD) have been conducted and compared [5,6,7]. However, these approaches cannot adequately quantify hemodynamic features because the spatiotemporal resolution of 4D flow MRI is limited and it is difficult to set patient-specific boundary conditions for CFD [8].…”

Section: Introductionmentioning

confidence: 99%

A practical approach for estimation of patient-specific intra-aneurysmal flows using variational data assimilation

Ichimura,

Yamada,

Watanabe

et al. 2024

Preprint

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Evaluation of hemodynamics is crucial to predict growth and rupture of cerebral aneurysms. Variational data assimilation (DA) is a powerful tool to characterize patient-specific intra-aneurysmal flows. The DA method inversely estimates a boundary condition in fluid equations using personalized flow data; however, its high computational cost in optimization problems makes its use impractical. This study proposes a practical DA approach to evaluate patient-specific intra-aneurysmal flows. To estimate personalized flows, a variational DA method was combined with computational fluid dynamics (CFD) analysis and observed intra-aneurysmal velocity data, and an inverse problem was solved to estimate the spatiotemporal velocity profile at a boundary of the aneurysm neck. To circumvent an ill-posed inverse problem, model order reduction based on a Fourier series expansion was used to describe temporal changes in state variables. In numerical validation using synthetic data from a direct CFD analysis, the present DA method achieved excellent agreement with the ground truth, with a velocity mismatch of approximately 18%. In flow estimations for three patient-specific datasets, the velocity mismatch for the present DA method was markedly lower than that for the direct CFD analysis and would mitigate unphysical velocity distributions in flow data from phase contract magnetic resonance imaging. By focusing only on the intra-aneurysmal region, the present DA approach provides an attractive way to evaluate personalized flows in aneurysms with greater reliability than conventional CFD and better efficiency than existing DA approaches.

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“…For instance, 4D flow MRI [7], one of the most advanced imaging techniques, allows the detection of a time-dependent blood flow field [8], the estimate of haemodynamics parameters as flow stasis, mean velocity [9], and particle tracking [10]. However, the resolution provided by 4D flow MRI might be not enough to accurately catch the complexity of cardiac flows and their transitional effects: formation of shear layers, small vortices, and their interactions [11,12,13,14,15]. For this reason, in-silico simulations of the heart, often combined with medical images, stand as a valuable tool for a more accurate descripition of blood flows and to estimate a number of haemodynamic indicators as the wall shear stress (WSS) [16,17,18,19].…”

Section: Introductionmentioning

confidence: 99%

Impact of Atrial Fibrillation on Left Atrium Haemodynamics: A Computational Fluid Dynamics Study

Corti¹,

Zingaro²,

Dedè³

et al. 2022

Preprint

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We analyze left atrium haemodynamics, highlighting differences among healthy individuals and patients affected by atrial fibrillation. The computational study is based on patient-specific geometries of the left atria to simulate blood flow dynamics. We devise a novel procedure aimed at recovering the boundary conditions for the 3D haemodynamics simulations, particularly useful in absence of specific ones provided by clinical measurements. With this aim, we introduce a parametric definition of the atria displacement, and we employ a closed-loop lumped parameter model of the whole cardiocirculatory system conveniently tuned on the basis of the patient characteristics. We evaluate a number of fluid dynamics indicators for the atrial haemodynamics, validating our numerical results in terms of several clinical measurements; we investigate the impact of geometrical and clinical features on the risk of thrombosis. To analyse the correlation of thrombus formation with atrial fibrillation, coherently with the medical evidence, we propose a novel indicator, which we call age stasis and that arises from the combination of Eulerian and Lagrangian quantities. This indicator identifies regions where the slow flow cannot rinse the chamber properly, accumulating stale blood particles and creating optimal conditions for clot formation.

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Comparison of Hemodynamic Visualization in Cerebral Arteries: Can Magnetic Resonance Imaging Replace Computational Fluid Dynamics?

Cited by 9 publications

References 42 publications

Improving Blood Flow Visualization of Recirculation Regions at Carotid Bulb in 4D Flow MRI Using Semi-Automatic Segmentation with ITK-SNAP

Improving Blood Flow Visualization of Recirculation Regions at Carotid Bulb in 4D Flow MRI Using Semi-Automatic Segmentation with ITK-SNAP

A practical approach for estimation of patient-specific intra-aneurysmal flows using variational data assimilation

Impact of Atrial Fibrillation on Left Atrium Haemodynamics: A Computational Fluid Dynamics Study

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