Purpose: To investigate wall shear rates in vivo in the common carotid, brachial, and superficial femoral arteries using very high resolution magnetic resonance imaging (MRI) phase contrast measurements.
Materials And Methods: Mean, maximum, and minimum wall shear rate and an oscillatory shear index were measured for 20 volunteers, aged 23.3 +/- 1.9 years, in the three arteries, using phase contrast imaging with 0.0625 mm2 resolution and three-dimensional paraboloid fitting.
Results: The superficial femoral artery had the lowest mean (130.3 +/- 13.1 second(-1)), maximum (735.8 +/- 32.4 second(-1)), and minimum (-224.5 +/- 17.0 second(-1)) wall shear rate, as well as the highest oscillatory shear index (0.21 +/- 0.02). All values were significantly different (P < 0.05) from both the brachial artery and the common carotid artery values. The highest mean (333.3 +/- 13.6 second(-1)) and minimum (117.9 +/- 24.5 second(-1)) wall shear rates and the lowest oscillatory shear index (0 +/- 0) were found in the common carotid artery.
Conclusion: It is possible to measure wall shear rate in vivo in different arteries using MRI with very high resolution. The findings exhibit the in vivo environment of wall shear rates and suggest a nonuniform distribution of wall shear rates throughout the arterial system.
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http://dx.doi.org/10.1002/jmri.10441 | DOI Listing |
Sci Rep
January 2025
Department of Engineering Mechanics, KTH Royal Institute of Technology, Stockholm, Sweden.
Aneurysm rupture is a life-threatening event, yet its underlying mechanisms remain largely unclear. This study investigated the fracture properties of the thoracic aneurysmatic aorta (TAA) using the symmetry-constraint Compact Tension (symconCT) test and compared results to native and enzymatic-treated porcine aortas' tests. With age, the aortic stiffness increased, and tissues ruptured at lower fracture energy [Formula: see text].
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
Bilayers of two-dimensional van der Waals materials that lack an inversion center can show a novel form of ferroelectricity, where certain stacking arrangements of the two layers lead to an interlayer polarization. Under an external out-of-plane electric field, a relative sliding between the two layers can occur, accompanied by an interlayer charge transfer and a ferroelectric switching. We show that the domain walls that mediate ferroelectric switching are a locus of strong attractive interactions between electrons.
View Article and Find Full Text PDFPulmonary artery (PA) flow analysis is crucial for understanding the progression of pulmonary hypertension (PH). We hypothesized that PA flow characteristics vary according to PH etiology. In this study, we used 4D flow cardiovascular magnetic resonance imaging (CMR) to compare PA flow velocity and wall shear stress (WSS) between patients with pulmonary arterial hypertension (PAH) and those with heart failure with preserved ejection fraction and pulmonary hypertension (PH-HFpEF).
View Article and Find Full Text PDFFront Bioeng Biotechnol
December 2024
School of Aeronautic Science and Engineering, Beihang University, Beijing, China.
Introduction: In-stent restenosis remains a significant challenge in coronary artery interventions. This study aims to explore the relationship between exercise intensity and stent design, focusing on the coupled response of the stent structure and hemodynamics at different exercise intensities.
Methods: A coupled balloon-stent-plaque-artery model and a fluid domain model reflecting structural deformation were developed to investigate the interaction between coronary stents and stenotic vessels, as well as their impact on hemodynamics.
Comput Biol Med
December 2024
University of Colorado Boulder, Paul M. Rady Department of Mechanical Engineering, Boulder, CO, USA; Biofrontiers Institute, University of Colorado, Boulder, CO, 80309, USA. Electronic address:
Breast cancer cells sense shear stresses in response to interstitial fluid flow in bone and induce specific biological responses. Computational fluid dynamics models have been instrumental in estimating these shear stresses to relate the cell mechanoresponse to exact mechanical signals, better informing experiment design. Most computational models greatly simplify the experimental and cell mechanical environments for ease of computation, but these simplifications may overlook complex cell-substrate mechanical interactions that significantly change shear stresses experienced by cells.
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