Wall shear stress calculation in ascending aorta using phase contrast magnetic resonance imaging. Investigating effective ways to calculate it in clinical practice
| Autor: | Efstathios P. Efstathopoulos, Ioannis Pantos, Odysseas Benekos, Georgios Patatoukas, Nikolaos Kelekis, Demosthenes G. Katritsis |
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| Rok vydání: | 2007 |
| Předmět: |
Adult
Male Biophysics General Physics and Astronomy Blood Pressure Sensitivity and Specificity Stress (mechanics) Young Adult Shear strength (soil) medicine.artery Elastic Modulus Ascending aorta Image Interpretation Computer-Assisted medicine Perpendicular Range (statistics) Shear stress Humans Radiology Nuclear Medicine and imaging Computer Simulation Aorta Aged Physics Models Cardiovascular Reproducibility of Results General Medicine Mechanics Blood flow Middle Aged Hagen–Poiseuille equation Magnetic Resonance Imaging cardiovascular system Female Stress Mechanical Shear Strength Blood Flow Velocity circulatory and respiratory physiology Biomedical engineering |
| Zdroj: | Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB). 24(4) |
| ISSN: | 1120-1797 |
| Popis: | Introduction There is growing evidence that atherosclerosis, as well as endothelial biology, depend on arterial wall shear stress (WSS). Several methods of WSS calculation with varying degrees of complexity have been proposed. This study aimed at investigating whether the most straightforward and easier to apply of these methods give comparable results in clinical practice. Methods Complete velocity encoding measurements using phase contrast magnetic resonance imaging were performed in 20 patients at a level perpendicular to the long axis of the ascending aorta approximately 2 cm above the aortic valve. WSS was calculated at this location on maximum systole. MR imaging was accomplished on a 1.5 T scanner. Four methods were applied to calculate WSS; three of them are based on the predictions of Poiseuille's theory of flow, while the last one is based on calculations resulting by the application of the definition of WSS. Results WSS calculated with the above mentioned methods was found to be in the range 4.2 ± 1.8 to 3.5 ± 1.7 dynes/m2. The velocity profile at the site of measurements can be described with a parabolic equation of the form u = a r 2 + b r + c with an average r2 = 0.83, which is in good agreement with Poiseuille's theory of flow. Comparison of the results shows no statistically significant differences between WSS measurements calculated with these methods. Discussion The four methods are equivalent in calculating WSS at the ascending aorta when blood flow velocities have a good parabolic distribution. |
| Databáze: | OpenAIRE |
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