Echocardiographic Particle Image Velocimetry: A Novel Technique for Quantification of Left Ventricular Blood Vorticity Pattern

doi:10.1016/j.echo.2009.09.007

Journal of the American Society of Echocardiography

Volume 23, Issue 1, January 2010, Pages 86-94

https://doi.org/10.1016/j.echo.2009.09.007 Get rights and content

Background

In this study, the functionality of echocardiographic particle imaging velocimetry (E-PIV) was compared with that of digital particle imaging velocimetry (D-PIV) in an in vitro model. In addition, its capability was assessed in the clinical in vivo setting to obtain the ventricular flow pattern in normal subjects, in patients with dilated cardiomyopathy, and in patients with mechanical and bioprosthetic mitral valves.

Methods

A silicon sac simulating the human left ventricle in combination with prosthetic heart valves, controlled by a pulsed-flow duplicator, was used as the in vitro model. Particle-seeded flow images were acquired (1) using a high-speed camera from the mid plane of the sac, illuminated by a laser sheet for D-PIV, and (2) using a Siemens Sequoia system at a frame rate of 60 Hz for E-PIV. Data analysis was performed with PIVview software for D-PIV and Omega Flow software for E-PIV. E-PIV processing was then applied to contrast echocardiographic image sets obtained during left ventricular cavity opacification with a lipid-shelled microbubble agent to assess spatial patterns of intracavitary flow in the clinical setting.

Results

The velocity vectors obtained using both the E-PIV and the D-PIV methods compared well for the direction of flow. The streamlines were also found to be similar in the data obtained using both methods. However, because of the superior spatial resolution of D-PIV, some smaller scale details were not revealed by E-PIV. The application of E-PIV to the human heart resulted in reproducible flow patterns in echocardiographic images taken within different time frames or by independent examiners.

Conclusions

The E-PIV technique appears to be capable of evaluating the major flow features in the ventricles. However, the bounded spatial resolution of ultrasound imaging limits the small-scale features of ventricular flow to be revealed.

Section snippets

Methods

Techniques that are based on PIV or, more generally, on optical flow measurements have been proven successful in several applied fields of science, ranging from turbulent fluid dynamics to optical motion recognition. The main challenge in the application of PIV to echocardiography, besides image quality (low signal-to-noise ratio), is the low ratio of spatial resolution to temporal resolution, which prevents the interpretation of the entire range of velocities in the human heart. Good results

In Vitro Results

The velocity fields computed by D-PIV are shown in Figure 2 (top row) at the peak of the filling wave, during inflow deceleration, at late diastole, and at the beginning of systole, respectively. The corresponding velocity fields obtained by E-PIV are also shown in Figure 2 (bottom row). Despite the differences in spatial resolution, dynamic range, and velocity accuracy between the two methods, the main physical features of intraventricular flow could be outlined. The flow presented an intense

Discussion

The aim of this study was to assess the validity of E-PIV for quantitative assessment of the intraventricular blood flow field. Accurate mapping of intraventricular flow provides novel opportunities to evaluate the role of vortices in ventricular function. Similar to any fluid dynamics phenomenon involving vortices, these flow structures are expected to play fundamental roles affecting the dynamics and the energetics of the left ventricle as a bifunctional pump. The presence of vortical

Conclusion

E-PIV is a novel technique for evaluating ventricular fluid dynamics, particularly for assessment of transmitral vortex ring formation. With this new technique, the velocity directions and streamlines can be drawn with reasonable confidence. E-PIV is also capable of evaluating the principal (large-scale) blood flow patterns in the left ventricle. The principal flow features, recirculation regions and vortices, can be detected in a visually reproducible scheme. As a result, this technique may

References (24)

W.Y. Kim et al.
Two-dimensional mitral flow velocity profiles in pig models using epicardial echo Doppler cardiography
J Am Coll Cardiol
(1994)
W.Y. Kim et al.
Left ventricular blood flow patterns in normal subjects: a quantitative analysis by three-dimensional magnetic resonance velocity mapping
J Am Soc Echocardiogr
(1995)
H. Reul et al.
Fluid mechanics of the natural mitral valve
J Biomech
(1981)
P.P. Sengupta et al.
Left ventricular isovolumic flow sequence during sinus and paced rhythms: new insights from use of high-resolution Doppler and ultrasonic digital particle imaging velocimetry
J Am Coll Cardiol
(2007)
G.-R. Hong et al.
Characterization and quantification of vortex flow in the human left ventricle by contrast echocardiography using vector particle image velocimetry
J Am Coll Cardiol Img
(2008)
P.P. Sengupta et al.
Left ventricular structure and function: basic science for cardiac imaging
J Am Coll Cardiol
(2006)
A. Kheradvar et al.
On mitral valve dynamics and its connection to early diastolic flow
Ann Biomed Eng
(2009)
A. Kheradvar et al.
Correlation between vortex ring formation and mitral annulus dynamics during ventricular rapid filling
ASAIO J
(2007)
P.J. Kilner et al.
Asymmetric redirection of flow through the heart
Nature
(2000)
B.J. Bellhouse
Fluid mechanics of a model mitral valve and left ventricle
Cardiovasc Res
(1972)

F. Domenichini et al.

Three-dimensional filling flow into a model left ventricle

J Fluid Mech

(2005)

H.B. Kim et al.

Development and validation of echo PIV

Exp Fluids

(2004)

Cited by (169)

Artificial intelligence-based speckle featurization and localization for ultrasound speckle tracking velocimetry
2024, Ultrasonics
Deep learning-based super-resolution ultrasound (DL-SRU) framework has been successful in improving spatial resolution and measuring the velocity field information of a blood flows by localizing and tracking speckle signals of red blood cells (RBCs) without using any contrast agents. However, DL-SRU can localize only a small part of the speckle signals of blood flow owing to ambiguity problems encountered in the classification of blood flow signals from ultrasound B-mode images and the building up of suitable datasets required for training artificial neural networks, as well as the structural limitations of the neural network itself. An artificial intelligence-based speckle featurization and localization (AI-SFL) framework is proposed in this study. It includes a machine learning-based algorithm for classifying blood flow signals from ultrasound B-mode images, dimensionality reduction for featurizing speckle patterns of the classified blood flow signals by approximating them with quantitative values. A novel and robust neural network (ResSU-net) is trained using the online data generation (ODG) method and the extracted speckle features. The super-resolution performance of the proposed AI-SFL and ODG method is evaluated and compared with the results of previous U-net and conventional data augmentation methods under in silico conditions. The predicted locations of RBCs by the AI-SFL and DL-SRU for speckle patterns of blood flow are applied to a PTV algorithm to measure quantitative velocity fields of the flow. Finally, the feasibility of the proposed AI-SFL framework for measuring real blood flows is verified under in vivo conditions.
Simultaneous visualization of flow fields and oxygen concentrations to unravel transport and metabolic processes in biological systems
2022, Cell Reports Methods
From individual cells to whole organisms, O₂ transport unfolds across micrometer- to millimeter-length scales and can change within milliseconds in response to fluid flows and organismal behavior. The spatiotemporal complexity of these processes makes the accurate assessment of O₂ dynamics via currently available methods difficult or unreliable. Here, we present “sensPIV,” a method to simultaneously measure O₂ concentrations and flow fields. By tracking O₂-sensitive microparticles in flow using imaging technologies that allow for instantaneous referencing, we measured O₂ transport within (1) microfluidic devices, (2) sinking model aggregates, and (3) complex colony-forming corals. Through the use of sensPIV, we find that corals use ciliary movement to link zones of photosynthetic O₂ production to zones of O₂ consumption. SensPIV can potentially be extendable to study flow-organism interactions across many life-science and engineering applications.
Blood flow patterns estimation in the left ventricle with low-rate 2D and 3D dynamic contrast-enhanced ultrasound
2021, Computer Methods and Programs in Biomedicine
Background and Objective: Left ventricle (LV) dysfunction always occurs at early heart-failure stages, producing variations in the LV flow patterns. Cardiac diagnostics may therefore benefit from flow-pattern analysis. Several visualization tools have been proposed that require ultrafast ultrasound acquisitions. However, ultrafast ultrasound is not standard in clinical scanners. Meanwhile techniques that can handle low frame rates are still lacking. As a result, the clinical translation of these techniques remains limited, especially for 3D acquisitions where the volume rates are intrinsically low.
Methods: To overcome these limitations, we propose a novel technique for the estimation of LV blood velocity and relative-pressure fields from dynamic contrast-enhanced ultrasound (DCE-US) at low frame rates. Different from other methods, our method is based on the time-delays between time-intensity curves measured at neighbor pixels in the DCE-US loops. Using Navier-Stokes equation, we regularize the obtained velocity fields and derive relative-pressure estimates. Blood flow patterns were characterized with regard to their vorticity, relative-pressure changes (dp/dt) in the LV outflow tract, and viscous energy loss, as these reflect the ejection efficiency.
Results: We evaluated the proposed method on 18 patients (9 responders and 9 non-responders) who underwent cardiac resynchronization therapy (CRT). After CRT, the responder group evidenced a significant (p<0.05) increase in vorticity and peak dp/dt, and a non-significant decrease in viscous energy loss. No significant difference was found in the non-responder group. Relative feature variation before and after CRT evidenced a significant difference (p<0.05) between responders and non-responders for vorticity and peak dp/dt. Finally, the method feasibility is also shown with 3D DCE-US.
Conclusions: Using the proposed method, adequate visualization and quantification of blood flow patterns are successfully enabled based on low-rate DCE-US of the LV, facilitating the clinical adoption of the method using standard ultrasound scanners. The clinical value of the method in the context of CRT is also shown.
Contrast-Enhanced High-Frame-Rate Ultrasound Imaging of Flow Patterns in Cardiac Chambers and Deep Vessels
2020, Ultrasound in Medicine and Biology
Cardiac function and vascular function are closely related to the flow of blood within. The flow velocities in these larger cavities easily reach 1 m/s, and generally complex spatiotemporal flow patterns are involved, especially in a non-physiologic state. Visualization of such flow patterns using ultrasound can be greatly enhanced by administration of contrast agents. Tracking the high-velocity complex flows is challenging with current clinical echographic tools, mostly because of limitations in signal-to-noise ratio; estimation of lateral velocities; and/or frame rate of the contrast-enhanced imaging mode. This review addresses the state of the art in 2-D high-frame-rate contrast-enhanced echography of ventricular and deep-vessel flow, from both technological and clinical perspectives. It concludes that current advanced ultrasound equipment is technologically ready for use in human contrast-enhanced studies, thus potentially leading to identification of the most clinically relevant flow parameters for quantifying cardiac and vascular function.
An Anatomically Shaped Mitral Valve for Hemodynamic Testing
2024, Cardiovascular Engineering and Technology
A clinician’s guide to understanding aortic 4D flow MRI
2023, Insights into Imaging

View all citing articles on Scopus

View full text

Echocardiographic Particle Image Velocimetry: A Novel Technique for Quantification of Left Ventricular Blood Vorticity Pattern

Background

Methods

Results

Conclusions

Section snippets

Methods

In Vitro Results

Discussion

Conclusion

J Am Coll Cardiol

J Am Soc Echocardiogr

J Biomech

J Am Coll Cardiol

J Am Coll Cardiol Img

J Am Coll Cardiol

On mitral valve dynamics and its connection to early diastolic flow

Ann Biomed Eng

Correlation between vortex ring formation and mitral annulus dynamics during ventricular rapid filling

ASAIO J

Asymmetric redirection of flow through the heart

Nature

Fluid mechanics of a model mitral valve and left ventricle

Cardiovasc Res

Three-dimensional filling flow into a model left ventricle

J Fluid Mech

Development and validation of echo PIV

Exp Fluids