scholarly journals Measurement of Blood Flow Field in Microcirculation by Means of High-Resolution PIV

2000 ◽  
Vol 20 (2Supplement) ◽  
pp. 37-40
Author(s):  
Yasuhiko SUGII ◽  
Astushi NAKANO ◽  
Shigeru NISHIO ◽  
Motomu MINAMIYAMA
Keyword(s):  
Blood Flow ◽  
High Resolution ◽  
Flow Field

scholarly journals Associations between haemodynamics and wall enhancement of intracranial aneurysm

2021 ◽  
pp. svn-2020-000636
Author(s):  
Miaoqi Zhang ◽  
Fei Peng ◽  
Xin Tong ◽  
Xin Feng ◽  
Yunduo Li ◽  
...  
Keyword(s):  
Blood Flow ◽  
High Resolution ◽  
Ordinal Regression ◽  
Parent Artery ◽  
Black Blood ◽  
4D Flow Mri ◽  
4D Flow ◽  
Unruptured Intracranial Aneurysms ◽  
Black Blood Mri ◽  
Flow Mri

Background and purposePrevious studies have reported about inflammation processes (IPs) that play important roles in aneurysm formation and rupture, which could be driven by blood flow. IPs can be identified using aneurysmal wall enhancement (AWE) on high-resolution black-blood MRI (BB-MRI) and blood flow haemodynamics can be demonstrated by four-dimensional-flow MRI (4D-flow MRI). Thus, this study investigated the associations between AWE and haemodynamics in unruptured intracranial aneurysms (IA) by combining 4D-flow MRI and high-resolution BB-MRI.Materials and methodsBetween April 2014 and October 2017, 48 patients with 49 unruptured IA who underwent both 4D-flow MRI and high-resolution BB-MRI were retrospectively included in this study. The haemodynamic parameters demonstrated using 4D-flow MRI were compared between different AWE patterns using the Kruskal-Wallis test and ordinal regression.ResultsThe results of Kruskal-Wallis test showed that the average wall shear stress in the IA (WSSavg-IA), maximum through-plane velocity in the adjacent parent artery, inflow jet patterns and the average vorticity in IA (vorticityavg-IA) were significantly associated with the AWE patterns. Ordinal regression analysis identified WSSavg-IA (p=0.002) and vorticityavg-IA (p=0.033) as independent predictors of AWE patterns.ConclusionA low WSS and low average vorticity were independently associated with a high AWE grade for IAs larger than 4 mm. Therefore, WSS and average vorticity could predict AWE and circumferential AWE.

scholarly journals Quantification of Hepatic Blood Flow Using a High-Resolution Phase-Contrast MRI Sequence With Compressed Sensing Acceleration

2015 ◽  
Vol 204 (3) ◽  
pp. 510-518 ◽  
Author(s):  
Hadrien A. Dyvorne ◽  
Ashley Knight-Greenfield ◽  
Cecilia Besa ◽  
Nancy Cooper ◽  
Julio Garcia-Flores ◽  
...  
Keyword(s):  
Blood Flow ◽  
High Resolution ◽  
Compressed Sensing ◽  
Hepatic Blood Flow ◽  
Phase Contrast ◽  
Phase Contrast Mri

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.

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