Validation of Echodynamography in Comparison with Particle-image Velocimetry

2019 ◽  
Vol 41 (6) ◽  
pp. 336-352 ◽  
Author(s):  
Sri Oktamuliani ◽  
Naoya Kanno ◽  
Moe Maeda ◽  
Kaoru Hasegawa ◽  
Yoshifumi Saijo
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Velocity ◽  
Relative Error ◽  
Radial Direction ◽  
Particle Image ◽  
Left Ventricular ◽  
Perpendicular Direction ◽  
Percentage Error ◽  
Doppler Velocity ◽  
Image Velocimetry

Echodynamography (EDG) is a computational method to estimate and visualize two-dimensional flow velocity vectors by applying dynamic flow theories to color Doppler echocardiography. The EDG method must be validated if applied to human cardiac flow function. However, a few studies of flow estimated have compared by EDG to the flow data were acquired by other methods. In this study, EDG was validated by comparing the analysis of estimating and visualizing flow velocity vectors obtained by original particle image velocimetry (PIV) based on a left ventricular (LV) phantom hydrogel (in vitro studies) and by EDG based on the virtual Doppler velocity. Velocity measured by PIV method and velocity estimated by EDG method in the perpendicular direction and the radial direction were compared. Regression analysis for the velocity estimated in the radial direction revealed an excellent correlation ([Formula: see text], slope = 0.96) and moderate correlation in the perpendicular direction ([Formula: see text], slope = 0.46). As revealed by the Bland–Altman plot, however, overestimations and higher relative error were observed in the perpendicular direction (0.51 ± 2.75 mm/s) and in the radial direction (–2.15 ± 21.13 mm/s). The percentage error of the norm-wise relative error of the velocity discrepancy is less than [Formula: see text], and velocity magnitude followed the same trends and are of comparable magnitude. These findings indicate that good estimates of velocity can be obtained by the EDG method. Therefore, the EDG method was appropriate for estimating and visualizing velocity vectors in clinical studies for higher measurement accuracy and reliability. The clinical in vivo application showed that the EDG method has the ability to visualize blood flow velocity vectors and differentiate the clinical information of vortex parameters both in normal and abnormal LV subjects. In conclusion, the EDG method has potentially greater clinical acceptance as a tool assessment of LV during the cardiac cycle.

High Resolution Particle Image Velocimetry and CH-PLIF Measurements and Analysis of a Shear Layer Stabilized Flame

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
C. W. Foley ◽  
I. Chterev ◽  
J. Seitzman ◽  
T. Lieuwen
Keyword(s):  
Particle Image Velocimetry ◽  
High Resolution ◽  
Shear Layer ◽  
Flow Velocity ◽  
Particle Image ◽  
Flame Stabilization ◽  
Flow Conditions ◽  
Local Flow ◽  
Image Velocimetry ◽  
Flow Velocities

Understanding the mechanisms and physics of flame stabilization and blowoff of premixed flames is critical toward the design of high velocity combustion devices. In the high bulk flow velocity situation typical of practical combustors, the flame anchors in shear layers where the local flow velocities are much lower. Within the shear layer, fluid strain deformation rates are very high and the flame can be subjected to significant stretch levels. The main goal of this work was to characterize the flow and stretch conditions that a premixed flame experiences in a practical combustor geometry and to compare these values to calculated extinction values. High resolution, simultaneous particle image velocimetry (PIV) and planar laser induced fluorescence of CH radicals (CH-PLIF) measurements are used to capture the flame edge and near-field stabilization region. When approaching lean limit extinction conditions, we note characteristic changes in the stretch and flow conditions experienced by the flame. Most notably, the flame becomes less critically stretched when fuel/air ratio is decreased. However, at these lean conditions, the flame is subject to higher mean flow velocities at the edge, suggesting less favorable flow conditions are present at the attachment point of the flame as blowoff is approached. These measurements suggest that blowoff of the flame from the shear layer is not directly stretch extinction induced, but rather the result of an imbalance between the speed of the flame edge and local tangential flow velocity.

Analysis of Airflow Velocity Field Characteristics of an Oat Cleaner Based on Particle Image Velocimetry Technology

2019 ◽  
Vol 35 (2) ◽  
pp. 193-201 ◽  
Author(s):  
Xinping Li ◽  
Jialiang Zhang ◽  
Jiangtao Ji
Keyword(s):  
Particle Image Velocimetry ◽  
Velocity Field ◽  
High Speed ◽  
Radial Direction ◽  
Particle Image ◽  
Longitudinal Section ◽  
Airflow Velocity ◽  
Cleaning Performance ◽  
Image Velocimetry ◽  
Cleaning Machine

Abstract.To improve the cleaning performance of oat sorting devices with a single-fan three-cylinder screen system, this study investigated the airflow velocity field of a cleaning machine using particle image velocimetry (PIV) technology. Specifically, an optimal cleaning performance can be described as one with no material idling under the optimal operating parameters of the oat cleaning machine, the measured airflow velocity field space is divided into nine representative longitudinal planes that can reflect airflow velocity characteristics in the longitudinal plane. The results showed that a phenomenon of airflow backflow occurred in the radial direction above the medium cylinder screen, the airflow velocity in each longitudinal section of the airflow velocity field was less uniform in the transverse distribution, a. The movement of oat extracts in the cleaning room was recorded by a high-speed digital video camera. The phenomenon of oat impurities moving along the airflow backflow direction, and a transverse flow irregularity appearing in the radial direction above the medium cylinder screen were observed. The grain loss rate and impurity rate of the oat cleaner were 1.53% and 1.25%, respectively, under optimal conditions. Therefore, to improve the cleaning performance of the cleaner, it is necessary to theoretically analyze the phenomenon of airflow backflow in the cleaner, which can provide a reference for the follow-up design and optimization of the structure of the cleaner. Keywords: Airstream, Analysis, Cleaning, Particle image velocimetry, Test, Velocity field.

Abstract 13873: Quantitative Characteristics of Left Ventricular Vortex Flow in the Short and Long Axis Views by High Frame Rate Echocardiographic Particle Image Velocimetry

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Haruhiko Abe ◽  
Kasumi Masuda ◽  
Toshihiko Asanuma ◽  
Hikaru Koriyama ◽  
Yukihiro Koretsune ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Vortex Flow ◽  
Cardiac Cycle ◽  
Particle Image ◽  
Left Ventricular ◽  
Frame Rate ◽  
Vortex Strength ◽  
High Frame Rate ◽  
Image Velocimetry ◽  
Quantitative Characteristics

Background: Vortex flow in the left ventricle (LV) has three-dimensional structure and plays an important role in avoiding excessive dissipation of energy. However, quantitative characteristics of long and short axis (LAX and SAX) vortex flow have not been elucidated. Echocardiographic particle image velocimetry (Echo-PIV) is an emerging technique to evaluate instantaneous vortical flow inside the LV. However, it has a limitation of underestimation of high velocities due to limited frame rate. Moreover, previous investigations have mainly focused on vortex from LAX view. Therefore, we used high frame rate Echo-PIV to quantitate vortex flow in SAX as well as in LAX views to understand characteristics of vortex three-dimensionally. Methods: Echocardiographic contrast images of the LV SAX and LAX were acquired from 8 open-chest healthy dogs. The acquisition frame rate was 135 frames per second and the contrast bubbles density was optimized for blood flow analysis. Echo-PIV analysis was performed off-line by using commercially available software and vorticity data were calculated in the region of interest (ROI) throughout the cardiac cycle. ROI was manually placed on the vortex. Vortex strength was defined as the averaged vorticity within the ROI. Results: In SAX, counterclockwise vortex was seen near the anterior wall, and in LAX clockwise vortex was seen in the anterior mid-ventricle. Both in SAX and LAX views, vortex strength showed significant phasic variations being largest in isovolumic contraction (vortex strength, SAX 9.2±2.3/s, p<0.001; LAX -12.0±2.4/s, p<0.001), and smallest in isovolumic relaxation (SAX -0.8±0.8/s, p<0.001; LAX -1.9±1.9/s, p<0.001). Conclusion: High frame rate Echo-PIV successfully demonstrated a complicated pattern of intracardiac vortex with phasic variation of its strength throughout a cardiac cycle in both SAX and LAX. This method may be a useful tool to assess physiological role of vortex in the flow dynamics.

Analysis of left ventricular fluid dynamics in dilated cardiomyopathy by echocardiographic particle image velocimetry

2017 ◽  
Vol 35 (1) ◽  
pp. 56-63 ◽  
Author(s):  
Chouchou Tang ◽  
Yizhong Zhu ◽  
Jing Zhang ◽  
Chengcheng Niu ◽  
Dan Liu ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Particle Image Velocimetry ◽  
Dilated Cardiomyopathy ◽  
Particle Image ◽  
Left Ventricular ◽  
Image Velocimetry

scholarly journals Evaluation of patients with a HeartMate 3 left ventricular assist device using echocardiographic particle image velocimetry

2020 ◽  
Author(s):  
Arend F. L. Schinkel ◽  
Sakir Akin ◽  
Mihai Strachinaru ◽  
Rahatullah Muslem ◽  
Dan Bowen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Particle Image Velocimetry ◽  
Particle Image ◽  
Vortex Formation ◽  
Left Ventricular ◽  
Flow Dynamics ◽  
Lv Function ◽  
Image Velocimetry ◽  
Intraventricular Flow ◽  
Blood Flow Dynamics

Abstract Purpose Poor left ventricular (LV) function may affect the physiological intraventricular blood flow and physiological vortex formation. The aim of this study was to investigate the pattern of intraventricular blood flow dynamics in patients with LV assist devices (LVADs) using echocardiographic particle image velocimetry. Materials and methods This prospective study included 17 patients (mean age 57 ± 11 years, 82% male) who had received an LVAD (HeartMate 3, Abbott Laboratories, Chicago, Illinois, USA) because of end-stage heart failure and poor LV function. Eleven (64%) patients had ischemic cardiomyopathy, and six patients (36%) had nonischemic cardiomyopathy. All patients underwent echocardiography, including intravenous administration of an ultrasound-enhancing agent (SonoVue, Bracco, Milan, Italy). Echocardiographic particle image velocimetry was used to quantify LV blood flow dynamics, including vortex formation (Hyperflow software, Tomtec imaging systems Gmbh, Unterschleissheim, Germany). Results Contrast-enhanced ultrasound was well tolerated in all patients and was performed without adverse reactions or side effects. The LVAD function parameters did not change during or after the ultrasound examination. The LVAD flow was on average 4.3 ± 0.3 L/min, and the speed was 5247 ± 109 rotations/min. The quantification of LV intraventricular flow demonstrated substantial impairment of vortex parameters. The energy dissipation, vorticity, and kinetic energy fluctuation indices were severely impaired. Conclusions Echo particle velocimetry is safe and feasible for the quantitative assessment of intraventricular flow in patients with an LVAD. The intraventricular LV flow and vortex parameters are severely impaired in these patients.

scholarly journals Application of Particle Image Velocimetry (PIV) for Measuring Water Velocity in Laboratory Sedimentation Tank

2017 ◽  
Vol 9 (3) ◽  
pp. 16
Author(s):  
King Kuok KUOK ◽  
Po Chan CHIU
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Velocity ◽  
Particle Image ◽  
Surface Flow ◽  
Camera Model ◽  
Food Dye ◽  
Sedimentation Tank ◽  
Tracer Particles ◽  
Tracking Process ◽  
Image Velocimetry

Over the past three decades, Particle Image Velocimetry (PIV), fundamentally based on pattern matching principles, has seen a rapid growth in its usage as a flow measurement technique. PIV is a ‘digital’ tracking process to measure the time taken for water to move from one point to the other. The particle displacements can be ascertained by measuring the movement of the fluid of interest from the images captured by a camera.  In this study, PIV is employed to measure surface flow velocity. The flow velocity was obtained by analyzing the series of captured images using MatPIV codes. The experiment was carried out at Swinburne Sarawak Fluid Lab. Digital SLR camera model used is Nikon D40X which is capable of taking 5 frames per second. Various tracer particles were used for the experiments include food dye, beads and ping pong balls. The experiments were conducted in a SOLTEQ Sedimentation Tank. Through the implementation of a standardized correction factor, the corrected PIV velocity has an error margin less than 5% which is deemed to be fairly accurate. The PIV velocity (V<sub>piv</sub>) results showed to be in good agreement with the actual velocity (V<sub>actual</sub>).

scholarly journals Optimized Time-Resolved Echo Particle Image Velocimetry– Particle Tracking Velocimetry Measurements Elucidate Blood Flow in Patients With Left Ventricular Thrombus

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Kaushik Sampath ◽  
Thura T. Harfi ◽  
Richard T. George ◽  
Joseph Katz
Keyword(s):  
Blood Flow ◽  
Particle Image Velocimetry ◽  
Particle Tracking ◽  
Particle Tracking Velocimetry ◽  
Particle Image ◽  
Left Ventricular ◽  
Time Resolved ◽  
Ventricular Thrombus ◽  
Image Velocimetry ◽  
Contrast Ultrasound

Contrast ultrasound is a widely used clinical tool to obtain real-time qualitative blood flow assessments in the heart, liver, etc. Echocardiographic particle image velocimetry (echo-PIV) is a technique for obtaining quantitative velocity maps from contrast ultrasound images. However, unlike optical particle image velocimetry (PIV), routine echo images are prone to nonuniform spatiotemporal variations in tracer distribution, making analysis difficult for standard PIV algorithms. This study introduces optimized procedures that integrate image enhancement, PIV, and particle tracking velocimetry (PTV) to obtain reliable time-resolved two-dimensional (2D) velocity distributions. During initial PIV analysis, multiple results are obtained by varying processing parameters. Optimization involving outlier removal and smoothing is used to select the correct vector. These results are used in a multiparameter PTV procedure. To demonstrate their clinical value, the procedures are implemented to obtain velocity and vorticity distributions over multiple cardiac cycles using images acquired from four left ventricular thrombus (LVT) patients. Phase-averaged data elucidate flow structure evolution over the cycle and are used to calculate penetration depth and strength of left ventricular (LV) vortices, as well as apical velocity induced by them. The present data are consistent with previous time-averaged results for the minimum vortex penetration depth associated with LVT occurrence. However, due to decay and fragmentation of LV vortices, as they migrate away from the mitral annulus, in two cases with high penetration, there is still poor washing near the resolved clot throughout the cycle. Hence, direct examination of entire flow evolution may be useful for assessing risk of LVT relapse before prescribing anticoagulants.

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