Theoretical investigation of mass transport to arterial walls in various blood flow regions— I. flow field and lipoprotein transport

1975 ◽  
Vol 27 (3-4) ◽  
pp. 231-262 ◽  
Author(s):  
Lloyd H. Back
Keyword(s):  
Blood Flow ◽  
Flow Field ◽  
Mass Transport ◽  
Theoretical Investigation ◽  
Arterial Walls

scholarly journals Mass Transport in Pulsatile Blood Flow with Intermittency through a Stenosed Aorta.

1999 ◽  
Vol 65 (632) ◽  
pp. 1362-1369
Author(s):  
Yoshiyuki WAKI ◽  
Takuji ISHIKAWA ◽  
Shuzo OSHIMA ◽  
Ryuichiro YAMANE ◽  
Motoharu HASEGAWA
Keyword(s):  
Blood Flow ◽  
Mass Transport ◽  
Pulsatile Blood Flow

scholarly journals Computed Tomography Image under Optimized Iterative Reconstruction Algorithm to Analyze the Characteristics of Blood Flow Field in Cerebral Aneurysm before and after Stent Implantation

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Kunyang Bao ◽  
Chao Liu ◽  
Jin Li ◽  
Xiang Liu ◽  
Wenzhang Luo ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Field ◽  
Cerebral Aneurysm ◽  
Iterative Reconstruction ◽  
Stent Implantation ◽  
Cerebral Aneurysms ◽  
Reconstruction Algorithm ◽  
Ct Images ◽  
Iterative Reconstruction Algorithm ◽  
The Difference

In order to analyze the change characteristics of blood flow field in cerebral aneurysms before and after stent implantation, this study first constructed an optimized iterative reconstruction algorithm to reconstruct CT images of patients with cerebral aneurysms and used it to solve the problem of image sharpness. In addition, backprojection image reconstruction algorithm and Fourier transform analytic method were introduced. According to the CT images of cerebral arteries of patients, the lesions were presented in a three-dimensional and visual way through the reconstructed three-dimensional images, thus achieving the effects of simulation and simulation. The results showed that the sensitivity, specificity, and accuracy of the optimized iterative reconstruction algorithm were 90.78%, 83.27%, and 94.82%, which were significantly higher than those of the backprojection image reconstruction algorithm and Fourier transform analysis method, and the difference was statistically significant ( P < 0.05 ). Before operation, the blood flow velocity in the neck of aneurysm was 7.35 × 10−2 m/s, the exit velocity was 1.51 × 10−1 m/s, and the maximum velocity appeared in the upstream part of the exit. After passing through the aneurysm, the blood flow velocity began to decrease gradually, forming a vortex at the top of the tumor. After stent implantation, the neck and outlet velocities of cerebral aneurysm were 9.352 × 10−2 m/s and 1.897 × 10−2 m/s, respectively. The velocity of blood flow decreased after entering the aneurysm, and there was no vortex at the top of the aneurysm. Among the outlet velocities of arterial blood vessels, the velocity before stent implantation was significantly lower than that after stent implantation, and the difference was statistically significant ( P < 0.05 ). Compared with prestent, the shear force distribution on the wall of cerebral aneurysm showed a significant decrease, and the difference was statistically significant ( P < 0.05 ). To sum up, pelvic floor ultrasound based on hybrid iterative reconstruction algorithm has high accuracy in diagnosing the changes of blood flow field in cerebral aneurysms. The application of CT images in the diagnosis of cerebral aneurysms can objectively provide imaging data for clinical practice and has high application value.

Reproduction of Blood Flow Field by Numerical Simulation Integrated With Ultrasonic Measurement With Noise

2009 ◽  
Author(s):  
Kenichi Funamoto ◽  
Toshiyuki Hayase ◽  
Yoshifumi Saijo ◽  
Tomoyuki Yambe
Keyword(s):  
Blood Flow ◽  
Flow Field ◽  
Gaussian Noise ◽  
Velocity Vector ◽  
Optimal Estimation ◽  
Ultrasonic Measurement ◽  
Measurement Noise ◽  
Governing Equations ◽  
Computational Accuracy ◽  
Numerical Studies

We have developed ultrasonic-measurement-integrated (UMI) simulation, in which feedback signals based on the optimal estimation of errors in the velocity vector determined by measured and computed Doppler velocities at feedback points are added to the governing equations (see Fig. 1) [1,2]. Our previous numerical studies showed the efficiency of UMI simulation for reproduction of blood flow field, as well as the transient and steady characteristics. However, in real ultrasonic measurement, noise is often included and may deteriorate the computational accuracy of UMI simulation. In this study, the effect of the ultrasonic measurement error due to Gaussian noise on UMI simulation was evaluated by a numerical experiment.

Flow field and mass transport analysis in arteries with longitudinal ridges

1976 ◽  
Vol 41 (6) ◽  
pp. 910-919 ◽  
Author(s):  
L. H. Back ◽  
D. W. Crawford ◽  
R. Barndt
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Shear Stresses ◽  
Time Varying ◽  
Intimal Thickening ◽  
Three Dimensional Flow ◽  
Longitudinal Vortices ◽  
Arterial Walls ◽  
Transport Analysis

Recent observations have indicated that the earliest lesions of atherosclerosis frequently take the form of longitudinal and helical ridges in arteries of man. Since longitudinal vortices are expected to be present in the troughs between the longitudinal ridges, an analysis was carried out to investigate the three-dimensional flow field and the trasport of lipoproteins and oxygen molecules to arterial walls in the presence of such vortices. The calculations revealed that local hypoxia and lipoprotein accumulation mayoccur at the ridges, leading to subsequent intimal thickening and ridge growth. Higher shear stresses, calculated in the troughs between ridges, may also partially damage the endothelium and lead to intimal thickening and subsequent merging of the ridges. Meaningful measurements are needed in vivo to determine the strength of the vortices, their time-varying behavior, and the actual transverse variations in shear stress, oxygen transport, and lipoprotein accumulation from trough to ridge regions, in order to appraise the present findings and to learn more about the observed progressive thickening and widening of ridges with increasing degrees of intimal thickening and atherosclerosis.

Natural History of Carotid Atherosclerosis in Relation to the Hemodynamic Environment

Angiology ◽  
2016 ◽  
Vol 68 (2) ◽  
pp. 109-118 ◽  
Author(s):  
Antonis I. Sakellarios ◽  
Paschalis Bizopoulos ◽  
Michail I. Papafaklis ◽  
Lambros Athanasiou ◽  
Themis Exarchos ◽  
...  
Keyword(s):  
Blood Flow ◽  
Natural History ◽  
Mass Transport ◽  
Carotid Atherosclerosis ◽  
Low Density Lipoprotein ◽  
Three Dimensional ◽  
Density Lipoprotein ◽  
Magnetic Resonance Data ◽  
History Of ◽  
Plaque Growth

Carotid atherosclerosis may lead to devastating clinical outcomes such as stroke. Data on the value of local factors in predicting progression in carotid atherosclerosis are limited. Our aim was to investigate the association of local endothelial shear stress (ESS) and low-density lipoprotein (LDL) accumulation with the natural history of atherosclerotic disease using a series of 3 time points of human magnetic resonance data. Three-dimensional lumen/wall reconstruction was performed in 12 carotids, and blood flow and LDL mass transport modeling were performed. Our results showed that an increase in plaque thickness and a decrease in lumen size were associated with low ESS and high LDL accumulation in the arterial wall. Low ESS (odds ratio [OR]: 2.99; 95% confidence interval [CI]: 2.31-3.88; P < .001 vs higher ESS) and high LDL concentration (OR: 3.26; 95% CI: 2.44-4.36; P < .001 vs higher LDL concentration) were significantly associated with substantial local plaque growth. Low ESS and high LDL accumulation both presented a diagnostic accuracy of 67% for predicting plaque growth regions. Modeling of blood flow and LDL mass transport show promise in predicting progression of carotid atherosclerosis.

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