scholarly journals Study on the Radial Sectional Velocity Distribution and Wall Shear Stress Associated With Carotid Artery Stenosis

2021 ◽  
Author(s):  
Zhiyong Song ◽  
Pengrui Zhu ◽  
Lianzhi Yang ◽  
Zhaohui Liu ◽  
Hua Li ◽  
...  
Keyword(s):  
Shear Stress ◽  
Carotid Artery ◽  
Wall Shear Stress ◽  
Flow Field ◽  
Velocity Distribution ◽  
Carotid Artery Stenosis ◽  
Central Area ◽  
Blood Velocity ◽  
Artery Stenosis ◽  
Wall Shear

Abstract BackgroundAtherosclerosis is an important cause of cardiovascular disease. The wall shear stress (WSS) is one of the key factors of plaque formation and dislodgement. Currently, WSS estimation is based on measurement of the blood velocity gradient. However, due to the lack of flow field measurements in carotid stenosis vessels, the two distribution forms (parabolic and non-parabolic) commonly considered in numerical simulations could cause WSS estimates to differ by more than 40%, which could seriously affect the accuracy of mechanical analysis. MethodsThis study was the first to apply 3D printing technology to create an experimental model of real-structure carotid arteries. Microparticle image velocimetry (micro-PIV) was adopted to comprehensively measure blood velocity field data at the stenosis location, providing experimental validation of numerical simulation (Fluent; finite volume method) results. Then, the flow field was simulated at a normal human heart rate (45-120 beats per minute). ResultsThis study revealed that when blood flowed across the carotid artery stenosis location, the velocity distribution was not parabolic but rather a plateau-shaped distribution, with a similar flow velocity in the central area (more than 65% of the total flow path). The WSS values calculated based on a parabolic velocity distribution and the maximum velocity were nearly 60% lower.ConclusionThis study provides a reliable method for WSS determination to better understand the vascular stenosis location and facilitate flow and shear force field research. In the future, it is necessary to carry out in-depth research on the relationship between the plaque shape, flow field distribution and WSS, and amendments to the calculated WSS for clinical stenosis should be proposed.

scholarly journals A PIV COMPARISON OF THE FLOW FIELD AND WALL SHEAR STRESS IN RIGID AND COMPLIANT MODELS OF HEALTHY CAROTID ARTERIES

2016 ◽  
Vol 17 (03) ◽  
pp. 1750041 ◽  
Author(s):  
PATRICK H. GEOGHEGAN ◽  
MARK C. JERMY ◽  
DAVID S. NOBES
Keyword(s):  
Shear Stress ◽  
Carotid Artery ◽  
Wall Shear Stress ◽  
Flow Field ◽  
Mechanical Response ◽  
Circulatory System ◽  
Rigid Boundary ◽  
Numerical Predictions ◽  
Wall Shear

Certain systems relevant to circulatory disease have walls which are neither rigid nor static, for example, the coronary arteries, the carotid artery and the heart chambers. In vitro modeling allows the fluid mechanics of the circulatory system to be studied without the ethical and safety issues associated with animal and human experiments. Computational methods in which the equations are coupled governing the flow and the elastic walls are maturing. Currently there is a lack of experimental data in compliant arterial systems to validate the numerical predictions. Previous experimental work has commonly used rigid wall boundaries, ignoring the effect of wall compliance. Particle Image Velocimetry is used to provide a direct comparison of both the flow field and wall shear stress (WSS) observed in experimental phantoms of rigid and compliant geometries representing an idealized common carotid artery. The input flow waveform and the mechanical response of the phantom are physiologically realistic. The results show that compliance affects the velocity profile within the artery. A rigid boundary causes severe overestimation of the peak WSS with a maximum relative difference of 61% occurring; showing compliance protects the artery from exposure to high magnitude WSS. This is important when trying to understand the development of diseases like atherosclerosis. The maximum, minimum and time averaged WSS in the rigid geometry was 2.3, 0.51 and 1.03[Formula: see text]Pa and in the compliant geometry 1.4, 0.58 and 0.84[Formula: see text]Pa, respectively.

scholarly journals Pravastatin Decreases Wall Shear Stress and Blood Velocity in the Internal Carotid Artery Without Affecting Flow Volume

Stroke ◽  
2007 ◽  
Vol 38 (4) ◽  
pp. 1374-1376 ◽  
Author(s):  
Frieke M.A. Box ◽  
Jeroen van der Grond ◽  
Anton J.M. de Craen ◽  
Inge H. Palm-Meinders ◽  
Rob J. van der Geest ◽  
...  
Keyword(s):  
Shear Stress ◽  
Carotid Artery ◽  
Wall Shear Stress ◽  
Internal Carotid Artery ◽  
Internal Carotid ◽  
Blood Velocity ◽  
Flow Volume ◽  
Wall Shear

Basic study on estimation method of wall shear stress in common carotid artery using blood flow imaging

2020 ◽  
Vol 59 (SK) ◽  
pp. SKKE16 ◽  
Author(s):  
Ryo Nagaoka ◽  
Kazuma Ishikawa ◽  
Michiya Mozumi ◽  
Magnus Cinthio ◽  
Hideyuki Hasegawa
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Carotid Artery ◽  
Wall Shear Stress ◽  
Common Carotid Artery ◽  
Estimation Method ◽  
Flow Imaging ◽  
Basic Study ◽  
Blood Flow Imaging ◽  
Wall Shear

scholarly journals Reproducibility of wall shear stress assessment with the paraboloid method in the internal carotid artery with velocity encoded MRI in healthy young individuals

2007 ◽  
Vol 26 (3) ◽  
pp. 598-605 ◽  
Author(s):  
Frieke M.A. Box ◽  
Rob J. van der Geest ◽  
Jeroen van der Grond ◽  
Matthias J.P. van Osch ◽  
Aeilko H. Zwinderman ◽  
...  
Keyword(s):  
Shear Stress ◽  
Carotid Artery ◽  
Wall Shear Stress ◽  
Internal Carotid Artery ◽  
Internal Carotid ◽  
Stress Assessment ◽  
Wall Shear

scholarly journals Hemodynamic parameters and vessel tortuosity: an investigation with a mesenterial vascular network

2017 ◽  
Vol 1 (4) ◽  
pp. 62-68
Author(s):  
Roberto Annunziata ◽  
Bettina Reglin ◽  
Axel Pries ◽  
Emanuele Trucco
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Oxygen Saturation ◽  
Wall Thickness ◽  
Blood Velocity ◽  
Vascular Network ◽  
Hemodynamic Parameters ◽  
Vessel Tortuosity ◽  
Wall Shear ◽  
Quantitative Definition

Purpose: The effect of hemodynamic parameters on vessel tortuosity remains un-clear. Here we investigate the correlation of tortuosity with a set of hemodynamicparameters in a mesenterial vascular network.Methods: A mesenterial vascular network of 389 vessels (131 arteries, 132 veins, and 126 capillaries) was imaged. Eleven hemodynamic parameters were measured (pressure, wall shear stress, diameter, blood velocity and flow, viscosity, haematocrit, partial oxygen saturation, oxygen saturation, wall thickness, and local vessel density). Tortuosity was assessed quantitatively with a validated algorithm and correlation computed with subsets of hemodynamic parameters selected by a lasso regressor.Results: Results suggest that tortuosity is related to pressure, wall shear stress, diameter, blood velocity, viscosity, partial but not full oxygen saturation, and wall thickness for the arteries; diameter, blood flow, hematocrit, and density for the veins; and viscosity (but not hematocrit), partial and full oxygen saturation, and density for the capillaries. The combination of hemodynamic parameters correlating best with tortuosity is the set of all parameters except density (r = 0.64, p < 0.01), using as tortuosity definition the set of tortuosity features (geometric measures) correlating best with a single hemodynamic factor for the arteries.Conclusion: This pilot suggests two general conclusions. First, the quantitative definition of tortuosity (i.e., the set of geometric features adopted) should be tuned to the specific data and problem considered. Second, tortuosity is caused by a combination of hemodynamic factors, not a single one.

Wall Shear Stress Measurement by Ultrafast Vector Flow Imaging for Atherosclerotic Carotid Stenosis

2019 ◽  
Author(s):  
Guillaume Goudot ◽  
Jonathan Poree ◽  
Olivier Pedreira ◽  
Lina Khider ◽  
Pierre Julia ◽  
...  
Keyword(s):  
Shear Stress ◽  
Carotid Artery ◽  
Wall Shear Stress ◽  
Carotid Stenosis ◽  
Common Carotid Artery ◽  
Frame Rate ◽  
Carotid Artery Plaque ◽  
Local Flow ◽  
Linear Probe ◽  
Wall Shear

Objective Carotid plaque vulnerability assessment could guide the decision to perform endarterectomy. Ultrafast ultrasound imaging (UF) can evaluate local flow velocities over an entire 2D image, allowing measurement of the wall shear stress (WSS). We aimed at evaluating the feasibility of WSS measurement in a prospective series of patients with carotid stenosis. Methods UF acquisitions, performed with a linear probe, had an effective frame rate of 5000 Hz. The flow velocity was imaged over the entire plaque area. WSS was computed with the vector field speed using the formula: with the blood velocity and μ, the blood viscosity. The WSS measurement method was validated using a calibrated phantom. In vivo, WSS was analyzed in 5 areas of the carotid wall: common carotid artery, plaque ascent, plaque peak, plaque descent, internal carotid artery. Results Good correlation was found between in vitro measurement and the theoretical WSS values (R2 = 0.95; p < 0.001). 33 patients were prospectively evaluated, with a median carotid stenosis degree of 80 % [75–85]. The maximum WSS value over the cardiac cycle follows the shape of the plaque with an increase during the ascent, reaching its maximum value of 3.25 Pa [2.26–4.38] at the peak of the plaque, and a decrease after passing of the peak (0.93 Pa [0.80–1.19]) lower than the WSS values in the non-stenotic areas (1.47 Pa [1.12–1.77] for the common carotid artery). Conclusion UF allowed local and direct evaluation of the plaque’s WSS, thus better characterizing local hemodynamics to identify areas of vulnerability. Key Points: 

3041Wall shear stress measurement by ultrafast vector flow imaging for atherosclerotic carotid stenosis

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
G Goudot ◽  
L Khider ◽  
O Pedreira ◽  
J M Poree ◽  
P Julia ◽  
...  
Keyword(s):  
Shear Stress ◽  
Carotid Artery ◽  
Wall Shear Stress ◽  
Internal Carotid Artery ◽  
Carotid Stenosis ◽  
Common Carotid Artery ◽  
Carotid Plaque ◽  
Internal Carotid ◽  
Plaque Vulnerability ◽  
Wall Shear

Abstract Background Carotid plaque vulnerability assessment is an important factor in guiding the decision to treat significant carotid stenosis. Ultrafast Ultrasound Imaging (UF) offers the possibility of evaluating local flow velocities over an entire 2D image, allowing access to velocity measurements in contact with the arterial wall and to measure the wall shear stress (WSS). Purpose To evaluate the feasibility of WSS measurement in a prospective series of patients with carotid stenosis. Methods A 7.5 MHz linear probe of an Aixplorer scanner was used. UF acquisitions had 3 tilted plane waves transmits (−10; 0; 10°) and an effective frame rate of 5000Hz. We evaluated the flow velocity in 5 areas of the carotid wall: common carotid artery (1), plaque ascent (2), plaque peak (3), plaque descent (4), internal carotid artery (5) (Figure). WSS was computed with the vector field speed using the following formula, WSS=μ·δn·v with v the blood velocity, n the normal vector to the vessel wall and μ, the blood viscosity, calculated from the hematocrit value for each patient. WSS measurement method was first validated using a laminar flow phantom and known viscosity. And then, 33 patients were then prospectively evaluated, with a median carotid stenosis degree of 80% [75–85]. Results Significant correlation was found between in vitro measurement and the theoretical WSS values (R2=0.95; p<0.001).In patients,the maximum WSS value over the cardiac cycle follows the shape of the plaque with an increase during the ascend, reaching its maximum value of 3.57 Pa [2.47–4.45] at the peak of the plaque, and a fall after passing the peak (0.99 Pa [0.8–1.32]) lower than the WSS values in the non-stenotic areas (1.55 Pa [1.13–1.90] for the common carotid artery) (Table). Table 1 Wall's area Wall shear stress (Pa) Min Max Delta 1. Common carotid artery 0.14 [0.05–0.27] 1.55 [1.13–1.90] 0.73 [0.55–0.96] 2. Plaque's ascent 0.39 [0.24–0.59] 2.63 [1.89–3.28] 1.20 [0.89–1.79] 3. Plaque's peak 0.60 [0.32–0.89] 3.57 [2.47–4.45] 1.78 [1.44–2.46] 4. Plaque's descent 0.16 [0.13–0.22] 0.99 [0.80–1.32] 0.52 [0.34–0.73] 5. Internal carotid artery 0.17 [0.13–0.35] 1.37 [1.04–1.75] 0.72 [0.50–0.87] Results are median [25th–75th percentile]. Figure 1 Conclusion UF provide reliable WSS values. High WSS was present at the peak of the plaque, whereas lowest WSS values were found at the post-stenotic zone. WSS evaluation may help to better characterize the carotid plaque vulnerability.

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