Effects of different non-Newtonian models on unsteady blood flow hemodynamics in patient-specific arterial models with in-vivo validation

2020 ◽  
Vol 186 ◽  
pp. 105185 ◽  
Author(s):  
Majid Abbasian ◽  
Mehrzad Shams ◽  
Ziba Valizadeh ◽  
Abouzar Moshfegh ◽  
Ashkan Javadzadegan ◽  
...  
Keyword(s):  
Blood Flow ◽  
Patient Specific ◽  
Unsteady Blood Flow ◽  
In Vivo Validation

scholarly journals Patient-specific computational haemodynamics associated with surgical creation of an arteriovenous fistula

2021 ◽  
Author(s):  
George Hyde-Linaker ◽  
Pauline Hall Barrientos ◽  
Sokratis Stoumpos ◽  
Asimina Kazakidi
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Disease Patient ◽  
Blood Flow Rate ◽  
Fold Increase ◽  
Transitional Flow ◽  
Patient Specific ◽  
Venous Anastomosis ◽  
End Stage

Abstract Despite arteriovenous fistulae (AVF) being the preferred vascular access for haemodialysis, high primary failure rates (30-70%) and low one-year patency rates (40-70%) hamper their use. The haemodynamics within the vessels of the fistula change significantly following surgical creation of the anastomosis and can be a surrogate of AVF success or failure. Computational fluid dynamics (CFD) can crucially predict AVF outcomes through robust analysis of a fistula’s haemodynamic patterns, which is impractical in-vivo. We present a proof-of-concept CFD framework for characterising the AVF blood flow prior and following surgical creation of a successful left radiocephalic AVF in a 20-year-old end-stage kidney disease patient. The reconstructed vasculature was generated utilising multiple contrast-enhanced magnetic resonance imaging (MRI) datasets. Large eddy simulations were conducted for establishing the extent of arterial and venous remodelling. Following anastomosis creation, a significant 2-3-fold increase in blood flow rate was induced downstream of the left subclavian artery. This was validated through comparison with post-AVF patient-specific phase-contrast data. The increased flow rate yielded an increase in time-averaged wall shear stress (TAWSS), a key marker of adaptive vascular remodelling. We have demonstrated TAWSS and oscillatory shear distributions of the transitional-flow in the venous anastomosis are predictive of AVF remodelling.

scholarly journals Quantification of coronary microvascular resistance using angiographic images for volumetric blood flow measurement: in vivo validation

2011 ◽  
Vol 300 (6) ◽  
pp. H2096-H2104 ◽  
Author(s):  
Zhang Zhang ◽  
Shigeho Takarada ◽  
Sabee Molloi
Keyword(s):  
Blood Flow ◽  
Swine Model ◽  
Distribution Analysis ◽  
Flow Probe ◽  
Flow Measurements ◽  
First Pass ◽  
Microvascular Resistance ◽  
Time Density ◽  
In Vivo Validation

Structural coronary microcirculation abnormalities are important prognostic determinants in clinical settings. However, an assessment of microvascular resistance (MR) requires a velocity wire. A first-pass distribution analysis technique to measure volumetric blood flow has been previously validated. The aim of this study was the in vivo validation of the MR measurement technique using first-pass distribution analysis. Twelve anesthetized swine were instrumented with a transit-time ultrasound flow probe on the proximal segment of the left anterior descending coronary artery (LAD). Microspheres were injected into the LAD to create a model of microvascular dysfunction. Adenosine (400 μg·kg−1·min−1) was used to produce maximum hyperemia. A region of interest in the LAD arterial bed was drawn to generate time-density curves using angiographic images. Volumetric blood flow measurements (Qa) were made using a time-density curve and the assumption that blood was momentarily replaced with contrast agent during the injection. Blood flow from the flow probe (Qp), coronary pressure (Pa), and right atrium pressure (Pv) were continuously recorded. Flow probe-based normalized MR (NMRp) and angiography-based normalized MR (NMRa) were calculated using Qp and Qa, respectively. In 258 measurements, Qa showed a strong correlation with the gold standard Qp (Qa = 0.90 Qp + 6.6 ml/min, r2 = 0.91, P < 0.0001). NMRa correlated linearly with NMRp (NMRa = 0.90 NMRp + 0.02 mmHg·ml−1·min−1, r2 = 0.91, P < 0.0001). Additionally, the Bland-Altman analysis showed a close agreement between NMRa and NMRp. In conclusion, a technique based on angiographic image data for quantifying NMR was validated using a swine model. This study provides a method to measure NMR without using a velocity wire, which can potentially be used to evaluate microvascular conditions during coronary arteriography.

An in vivo validation of quantitative blood flow imaging in arteries and veins using magnetic resonance phase-shift techniques

1991 ◽  
Vol 12 (2) ◽  
pp. 117-126 ◽  
Author(s):  
A. C. VAN ROSSUM ◽  
M. SPRENGER ◽  
F. C. VISSER ◽  
K. H. PEELS ◽  
J. VALK ◽  
...  
Keyword(s):  
Blood Flow ◽  
Magnetic Resonance ◽  
Phase Shift ◽  
Flow Imaging ◽  
Blood Flow Imaging ◽  
Arteries And Veins ◽  
In Vivo Validation

Computational Study on the Effects of Peripheral Vessel Network on Blood Flow in the Arterial Circle of Willis

2007 ◽  
Author(s):  
Shigefumi Tokuda ◽  
Takeshi Unemura ◽  
Marie Oshima
Keyword(s):  
Numerical Simulation ◽  
Blood Flow ◽  
Boundary Conditions ◽  
Vascular System ◽  
Computational Study ◽  
Circulatory System ◽  
Biological Data ◽  
Patient Specific ◽  
Peripheral Vessel

Cerebrovascular disorder such as subarachnoid hemorrhage (SAH) is 3rd position of the cause of death in Japan [1]. Its initiation and growth are reported to depend on hemodynamic factors, particularly on wall shear stress or blood pressure induced by blood flow. In order to investigate the information on the hemodynamic quantities in the cerebral vascular system, the authors have been developing a computational tool using patient-specific modeling and numerical simulation [2]. In order to achieve an in vivo simulation of living organisms, it is important to apply appropriate physiological conditions such as physical properties, models, and boundary conditions. Generally, the numerical simulation using a patient-specific model is conducted for a localized region near the research target. Although the analysis region is only a part of the circulatory system, the simulation has to include the effects from the entire circulatory system. Many studies have carried out to derive the boundary conditions to model in vivo environment [3–5]. However, it is not easy to obtain the biological data of cerebral arteries due to head capsule.

scholarly journals 1050: Cross-modality, in-vivo validation of 4D-Flow MRI evaluation of uterine artery blood flow in human pregnancy

2019 ◽  
Vol 220 (1) ◽  
pp. S673-S674
Author(s):  
Nadav Schwartz ◽  
Eileen Hwuang ◽  
Ana Rodriguez-Soto ◽  
Felix Wehrli ◽  
Marta Vidorreta ◽  
...  
Keyword(s):  
Blood Flow ◽  
Uterine Artery ◽  
Artery Blood Flow ◽  
4D Flow Mri ◽  
4D Flow ◽  
Human Pregnancy ◽  
Flow Mri ◽  
Mri Evaluation ◽  
In Vivo Validation

CFD Challenge: Solutions Using the Commercial Solver Fluent and the Open-Source Solver OpenFOAM

2012 ◽  
Author(s):  
P. Berg ◽  
G. Janiga ◽  
D. Thévenin
Keyword(s):  
Blood Flow ◽  
Cerebral Aneurysms ◽  
Flow Simulation ◽  
Patient Specific ◽  
Post Processing ◽  
Close Collaboration ◽  
Blood Flow Simulation ◽  
Unsteady Blood Flow ◽  
Commercial Solver ◽  
Considerable Experience

During the last decade, the research group in Magdeburg investigated the hemodynamics in cerebral aneurysms in close collaboration with experts from the fields of visualization and neuroradiology. Thanks to this, a considerable experience has been collected concerning unsteady blood flow simulation and analyses, involving a steadily increasing number of patient-specific aneurysms. Intermediate results have been presented at several VISC challenges. The simulations regarding this CFD Challenge as well as the post-processing have been carried out by the doctoral student Philipp Berg.

Sign in / Sign up

Export Citation Format

Share Document