scholarly journals Simulation of Brisk and Fast Phase-Contrast Magnetic Resonance Imaging by Computational Fluid Dynamics

2003 ◽  
Author(s):  
Bradley L. Hershey ◽  
Mark Doyle ◽  
Eduardo Kortright ◽  
Andreas Anayiotos
Keyword(s):  
Magnetic Resonance Imaging ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Magnetic Resonance ◽  
Phase Contrast ◽  
Sampling Rate ◽  
Sampling Strategy ◽  
Sparse Sampling ◽  
Resonance Imaging ◽  
Sampling Schemes

Cardiac synchronized magnetic resonance imaging of flowfields has suffered due to the relatively long acquisition times required. We developed a rapid MRI approach, BRISK PCA (Block Regional Interpolation Scheme for k-space Phase Contrast Angiography) which was simulated here using data generated by computational fluid dynamics to investigate the role of interpolation and segmentation on the accuracy and efficiency of the method. BRISK differs from other sparse sampling schemes in that the sampling rate is a function of the position in k-space and interpolation is used to generate data points not directly acquired. Combined with conventional segementation, this allows more efficient use of time, resulting in rapid acquisitions with good spatial and temporal resolution. FAST (Fourier AcquiSition in Time) is a similar sparse sampling strategy that varies the segmentation factor, rather than the sampling rate, as a function of k-space position. BRISK and FAST can be performed in nearly equally scan times. However, deviation from ideal in the FAST data was highly dependant on the starting phase of the flow waveform, while BRISK was immune to such variation. Simulations showed that BRISK (up to segmentation factor 5) and FAST 5 retained excellent axial-velocity accuracy, but the accuracy of FAST was variable and dependent on waveform characteristics.

Estimating the Hemodynamic Impact of Interventional Treatments of Aneurysms

Neurosurgery ◽  
2006 ◽  
Vol 59 (2) ◽  
pp. E429-E430 ◽  
Author(s):  
Gabriel Acevedo-Bolton ◽  
Liang-Der Jou ◽  
Bradley P. Dispensa ◽  
Michael T. Lawton ◽  
Randall T. Higashida ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Magnetic Resonance ◽  
Phase Contrast ◽  
Resonance Imaging ◽  
Contrast Magnetic Resonance Imaging ◽  
Phase Contrast Magnetic Resonance ◽  
Contrast Magnetic Resonance

Abstract OBJECTIVE: The goal of this study was to use phase-contrast magnetic resonance imaging and computational fluid dynamics to estimate the hemodynamic outcome that might result from different interventional options for treating a patient with a giant fusiform aneurysm. METHODS: We followed a group of patients with giant intracranial aneurysms who have no clear surgical options. One patient demonstrated dramatic aneurysm growth and was selected for further analysis. The aneurysm geometry and input and output flow conditions were measured with contrast-enhanced magnetic resonance angiography and phase-contrast magnetic resonance imaging. The data was imported into a computational fluid dynamics program and the velocity fields and wall shear stress distributions were calculated for the presenting physiological condition and for cases in which the opposing vertebral arteries were either occluded or opened. These models were validated with in vitro flow experiments using a geometrically exact silicone flow phantom. RESULTS: Simulation indicated that altering the flow ratio in the two vertebrals would deflect the main blood jet into the aneurysm belly, and that this would likely reduce the extent of the region of low wall shear stress in the growth zone. CONCLUSIONS: Computational fluid dynamics flow simulations in a complex patient-specific aneurysm geometry were validated by in vivo and in vitro phase-contrast magnetic resonance imaging, and were shown to be useful in modeling the likely hemodynamic impact of interventional treatment of the aneurysm.

A perspective review: Technical study of combining phase contrast magnetic resonance imaging and computational fluid dynamics for blood flow on carotid bifurcation artery

2020 ◽  
Vol 14 (4) ◽  
pp. 7609-7621
Author(s):  
Mohd Azrul Hisham Mohd Adib ◽  
Lim Sheh Hong ◽  
Mohd Shafie Abdullah ◽  
Radhiana Hassan ◽  
Shigeo Wada
Keyword(s):  
Magnetic Resonance Imaging ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Blood Flow ◽  
Magnetic Resonance ◽  
Phase Contrast ◽  
Resonance Imaging ◽  
Contrast Magnetic Resonance Imaging ◽  
Phase Contrast Magnetic Resonance ◽  
Contrast Magnetic Resonance

Nowadays, the knowledge of precise blood flow patterns in human blood vessels, especially focusing on Carotid Bifurcations Artery (CBA) area by using computational and modern techniques are very important to develop our understanding regarding to human diseases for both essential research and clinical treatment. This paper tends to discuss the progress regarding to the integration between Phase Contrast Magnetic Resonance Imaging (PC-MRI) and Computational Fluid Dynamics (CFD), specifically to the human diseases. We technically define the model geometry reconstruction, review both PC-MRI and CFD methods to create mesh models, obtain boundary conditions, define the governing equations in CFD, define the material properties, and assumptions used in running the CFD simulations. Detailed information on PC-MRI and CFD is provided in tables, such as the MRI setup, software used, CFD model setup, measurement parameter, and summary of the result contribution from each reviewed article. Numerous fusions between PC-MRI and CFD are specified by summarizing the investigation carried out by significant group’s research, reviewing the important outcomes, and discussing the techniques, drawbacks and possibilities for further study. We hope that this perspective analysis will encourage a fusion of PC-MRI and CFD research contributing to continuous advancement of human health with close cooperation and collaboration among clinicians and engineers.

Cerebral Blood Flow in a Healthy Circle of Willis and Two Intracranial Aneurysms: Computational Fluid Dynamics Versus Four-Dimensional Phase-Contrast Magnetic Resonance Imaging

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Philipp Berg ◽  
Daniel Stucht ◽  
Gábor Janiga ◽  
Oliver Beuing ◽  
Oliver Speck ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Magnetic Resonance ◽  
Boundary Conditions ◽  
Intracranial Aneurysms ◽  
Phase Contrast ◽  
Resonance Imaging ◽  
Phase Contrast Magnetic Resonance ◽  
Contrast Magnetic Resonance

Computational fluid dynamics (CFD) opens up multiple opportunities to investigate the hemodynamics of the human vascular system. However, due to numerous assumptions the acceptance of CFD among physicians is still limited in practice and validation through comparison is mandatory. Time-dependent quantitative phase-contrast magnetic resonance imaging PC-MRI measurements in a healthy volunteer and two intracranial aneurysms were carried out at 3 and 7 Tesla. Based on the acquired images, three-dimensional (3D) models of the aneurysms were reconstructed and used for the numerical simulations. Flow information from the MR measurements were applied as boundary conditions. The four-dimensional (4D) velocity fields obtained by CFD and MRI were qualitatively as well as quantitatively compared including cut planes and vector analyses. For all cases a high similarity of the velocity patterns was observed. Additionally, the quantitative analysis revealed a good agreement between CFD and MRI. Deviations were caused by minor differences between the reconstructed vessel models and the actual lumen. The comparisons between diastole and systole indicate that relative differences between MRI and CFD are intensified with increasing velocity. The findings of this study lead to the conclusion that CFD and MRI agree well in predicting intracranial velocities when realistic geometries and boundary conditions are provided. Due to the considerably higher temporal and spatial resolution of CFD compared to MRI, complex flow patterns can be further investigated in order to evaluate their role with respect to aneurysm formation or rupture. Nevertheless, special care is required regarding the vessel reconstruction since the geometry has a major impact on the subsequent numerical results.

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