scholarly journals On the stable estimation of flow geometry and wall shear stress from magnetic resonance images

2019 ◽  
Vol 35 (9) ◽  
pp. 095001 ◽  
Author(s):  
H Egger ◽  
G Teschner
Keyword(s):  
Shear Stress ◽  
Magnetic Resonance ◽  
Wall Shear Stress ◽  
Magnetic Resonance Images ◽  
Flow Geometry ◽  
Stable Estimation ◽  
Wall Shear

scholarly journals Wall Shear Stress Measurement Using Phase Contrast Magnetic Resonance Imaging with Phase Contrast Magnetic Resonance Angiography in Arteriovenous Polytetrafluoroethylene Grafts

Angiology ◽  
2009 ◽  
Vol 60 (4) ◽  
pp. 441-447 ◽  
Author(s):  
Sanjay Misra ◽  
Alex A. Fu ◽  
Khamal D. Misra ◽  
James F. Glockner ◽  
Debabrata Mukhopadhyay
Keyword(s):  
Magnetic Resonance Imaging ◽  
Shear Stress ◽  
Magnetic Resonance ◽  
Wall Shear Stress ◽  
Phase Contrast ◽  
Resonance Imaging ◽  
Phase Contrast Magnetic Resonance ◽  
Venous Stenosis ◽  
Contrast Magnetic Resonance ◽  
Wall Shear

Purpose The purpose of the present article was to determine the changes in luminal vessel area, blood flow, and wall shear stress in both the inflow artery and the venous stenosis of arteriovenous polytetrafluoroethylene (PTFE) grafts. Methods and materials Polytetrafluoroethylene grafts were placed from the carotid artery to the ipsilateral jugular vein in 8 castrated juvenile male pigs. Contrast-enhanced magnetic resonance angiography (MRA) with cine phase-contrast magnetic resonance imaging (MRI) was performed 2 weeks after graft placement. Results The mean wall shear stress at the venous stenosis was 4 times higher than the control vein, while the inflow artery was only 2-fold higher. By day 14, venous stenosis had formed, which was characterized by narrowed area and elevated blood flow. Conclusion By day 14, there is venous stenosis formation in porcine arteriovenous PTFE grafts with increased shear stress with decreased area when compared to control vein.

scholarly journals ESTIMATION OF WALL SHEAR STRESS USING 4D FLOW CARDIOVASCULAR MRI AND COMPUTATIONAL FLUID DYNAMICS

2016 ◽  
Vol 17 (03) ◽  
pp. 1750046 ◽  
Author(s):  
E. SOUDAH ◽  
J. CASACUBERTA ◽  
P. J. GAMEZ-MONTERO ◽  
J. S. PÉREZ ◽  
M. RODRÍGUEZ-CANCIO ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Blood Flow ◽  
Shear Stress ◽  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Wall Shear Stress ◽  
Thoracic Aorta ◽  
4D Flow ◽  
Wall Shear

In the last few years, wall shear stress (WSS) has arisen as a new diagnostic indicator in patients with arterial disease. There is a substantial evidence that the WSS plays a significant role, together with hemodynamic indicators, in initiation and progression of the vascular diseases. Estimation of WSS values, therefore, may be of clinical significance and the methods employed for its measurement are crucial for clinical community. Recently, four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has been widely used in a number of applications for visualization and quantification of blood flow, and although the sensitivity to blood flow measurement has increased, it is not yet able to provide an accurate three-dimensional (3D) WSS distribution. The aim of this work is to evaluate the aortic blood flow features and the associated WSS by the combination of 4D flow cardiovascular magnetic resonance (4D CMR) and computational fluid dynamics technique. In particular, in this work, we used the 4D CMR to obtain the spatial domain and the boundary conditions needed to estimate the WSS within the entire thoracic aorta using computational fluid dynamics. Similar WSS distributions were found for cases simulated. A sensitivity analysis was done to check the accuracy of the method. 4D CMR begins to be a reliable tool to estimate the WSS within the entire thoracic aorta using computational fluid dynamics. The combination of both techniques may provide the ideal tool to help tackle these and other problems related to wall shear estimation.

Allometric scaling of wall shear stress from mice to humans: quantification using cine phase-contrast MRI and computational fluid dynamics

2006 ◽  
Vol 291 (4) ◽  
pp. H1700-H1708 ◽  
Author(s):  
Joan M. Greve ◽  
Andrea S. Les ◽  
Beverly T. Tang ◽  
Mary T. Draney Blomme ◽  
Nathan M. Wilson ◽  
...  
Keyword(s):  
Shear Stress ◽  
Magnetic Resonance ◽  
Wall Shear Stress ◽  
Cardiovascular System ◽  
Phase Contrast ◽  
Scaling Laws ◽  
Allometric Scaling ◽  
Scaling Exponent ◽  
Infrarenal Aorta ◽  
Wall Shear

Allometric scaling laws relate structure or function between species of vastly different sizes. They have rarely been derived for hemodynamic parameters known to affect the cardiovascular system, e.g., wall shear stress (WSS). This work describes noninvasive methods to quantify and determine a scaling law for WSS. Geometry and blood flow velocities in the infrarenal aorta of mice and rats under isoflurane anesthesia were quantified using two-dimensional magnetic resonance angiography and phase-contrast magnetic resonance imaging at 4.7 tesla. Three-dimensional models constructed from anatomic data were discretized and used for computational fluid dynamic simulations using phase-contrast velocity imaging data as inlet boundary conditions. WSS was calculated along the infrarenal aorta and compared between species to formulate an allometric equation for WSS. Mean WSS along the infrarenal aorta was significantly greater in mice and rats compared with humans (87.6, 70.5, and 4.8 dyn/cm2, P < 0.01), and a scaling exponent of −0.38 ( R2 = 0.92) was determined. Manipulation of the murine genome has made small animal models standard surrogates for better understanding the healthy and diseased human cardiovascular system. It has therefore become increasingly important to understand how results scale from mouse to human. This noninvasive methodology provides the opportunity to serially quantify changes in WSS during disease progression and/or therapeutic intervention.

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