Intracardiac Vortex Dynamics by High-Frame-Rate Doppler Vortography—In Vivo Comparison With Vector Flow Mapping and 4-D Flow MRI

2017 ◽  
Vol 64 (2) ◽  
pp. 424-432 ◽  
Author(s):  
Julia Faurie ◽  
Mathilde Baudet ◽  
Kondo Claude Assi ◽  
Dominique Auger ◽  
Guillaume Gilbert ◽  
...  
Keyword(s):  
Vortex Dynamics ◽  
Frame Rate ◽  
Flow Mapping ◽  
High Frame Rate ◽  
Vector Flow Mapping ◽  
Flow Mri

Spontaneous Extension Wave for In Vivo Assessment of Arterial Wall Anisotropy

2021 ◽  
Author(s):  
Dan Ran ◽  
Jinping Dong ◽  
He Li ◽  
Wei-Ning Lee
Keyword(s):  
Carotid Artery ◽  
Arterial Wall ◽  
Guided Wave ◽  
Frame Rate ◽  
Mechanical Anisotropy ◽  
Natural Wave ◽  
High Frame Rate ◽  
Longitudinal Stiffness ◽  
Anisotropy Index

Another type of natural wave, traced from longitudinal wall motion and propagation along the artery, is unprecedentedly observed in our in vivo human carotid artery experiments. We coin it as extension wave (EW) and hypothesize that EW velocity (EWV) is associated with arterial longitudinal stiffness. The EW is thus assumed to complement the PW, whose velocity (PWV) is tracked from the radial wall displacement and linked to arterial circumferential stiffness through the Moens-Korteweg equation, as indicators for arterial mechanical anisotropy quantification by noninvasive high-frame-rate ultrasound. The relationship between directional arterial stiffnesses and the two natural wave speeds was investigated in wave theory, finite-element simulations based on isotropic and anisotropic arterial models, and in vivo human common carotid artery (N=10) experiments. Excellent agreement between the theory and simulations showed that EWV was 2.57 and 1.03 times higher than PWV in an isotropic and an anisotropic carotid artery model, respectively, while in vivo EWV was consistently lower than PWV in all 10 healthy human subjects. A strong linear correlation was substantiated in vivo between EWV and arterial longitudinal stiffness quantified by a well-validated vascular guided wave imaging technique (VGWI). We thereby proposed a novel index calculated as EWV2/PWV2 as an alternative to assess arterial mechanical anisotropy. Simulations and in vivo results corroborated the effect of mechanical anisotropy on the propagation of spontaneous waves along the arterial wall. The proposed anisotropy index demonstrated the feasibility of the concurrent EW and PW imaged by high frame-rate ultrasound in grading of arterial wall anisotropy.

Preliminary study on estimation of flow velocity vectors using focused transmit beams

2021 ◽  
Author(s):  
Hideyuki Hasegawa ◽  
Michiya Mozumi ◽  
Masaaki Omura ◽  
Ryo Nagaoka ◽  
Kozue Saito
Keyword(s):  
Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Soft Tissues ◽  
Estimation Error ◽  
Frame Rate ◽  
High Frame Rate ◽  
In Vivo Measurement ◽  
Preliminary Study

Abstract High-frame-rate ultrasound imaging with plane wave transmissions is a predominant method for blood flow imaging, and methods for estimation of blood flow velocity vectors have been developed based on high-frame-rate imaging. On the other hand, in imaging of soft tissues, such as arterial walls and atherosclerotic plaques, high-frame-rate imaging sometimes suffers from high-level clutters. Even in observation of the arterial wall with a focused transmit beam, it would be highly beneficial if blood flow velocity vectors could be estimated simultaneously. We conducted a preliminary study on estimation of blood flow velocity vectors based on a multi-angle Doppler method with focused transmit beam and parallel receive beamforming. It was shown that the lowest estimation error was achieved at a steering angle of 25 degrees by simulation. Also, velocity vectors with typical velocity magnitudes and directions could be obtained by the proposed method in in vivo measurement of a carotid artery.

scholarly journals Physics-constrained intraventricular vector flow mapping by color Doppler

2021 ◽  
Author(s):  
Florian Vixege ◽  
Alain Berod ◽  
Yunyun Sun ◽  
Simon Mendez ◽  
Olivier Bernard ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Optimization Problem ◽  
Regularization Parameter ◽  
Color Doppler ◽  
Scalar Fields ◽  
Patient Specific ◽  
Polar Coordinate System ◽  
Flow Mapping ◽  
Vector Flow Mapping

Abstract Color Doppler by transthoracic echocardiography creates two-dimensional fan-shaped maps of blood velocities in the cardiac cavities. It is a one-component velocimetric technique since it only returns the velocity components parallel to the ultrasound beams. Intraventricular vector flow mapping (iVFM) is a method to recover the blood velocity vectors from the Doppler scalar fields in an echocardiographic three-chamber view. We improved our iVFM numerical scheme by imposing physical constraints. The iVFM consisted in minimizing regularized Doppler residuals subject to the condition that two fluid-dynamics constraints were satisfied, namely planar mass conservation, and free-slip boundary conditions. The optimization problem was solved by using the Lagrange multiplier method. A finite-difference discretization of the optimization problem, written in the polar coordinate system centered on the cardiac ultrasound probe, led to a sparse linear system. The single regularization parameter was determined automatically for non-supervision considerations. The physics-constrained method was validated using realistic intracardiac flow data from a patient-specific CFD (computational fluid dynamics) model. The numerical evaluations showed that the iVFM-derived velocity vectors were in very good agreement with the CFD-based original velocities, with relative errors ranged between 0.3 and 12%. We calculated two macroscopic measures of flow in the cardiac region of interest, the mean vorticity and mean stream function, and observed an excellent concordance between physics-constrained iVFM and CFD. The capability of physics-constrained iVFM was finally tested with in vivo color Doppler data acquired in patients routinely examined in the echocardiographic laboratory. The vortex that forms during the rapid filling was deciphered. The physics-constrained iVFM algorithm is ready for pilot clinical studies and is expected to have a significant clinical impact on the assessment of diastolic function.

scholarly journals Loss of apical suction assessed by noninvasive pressure differences and twist in acute heart failure: a novel method using vector flow mapping

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
S Ido ◽  
K Masuda ◽  
S Yoshimura ◽  
H Tanaka ◽  
M Stugaard
Keyword(s):  
Heart Failure ◽  
Acute Heart Failure ◽  
Diastolic Pressure ◽  
Color Doppler ◽  
Left Ventricular ◽  
Frame Rate ◽  
Flow Mapping ◽  
Vector Flow Mapping ◽  
Funding Sources ◽  
Novel Method

Abstract Background Early diastolic intraventricular pressure difference (IVPD) reflects left ventricular (LV) apical suction, and IVPD is closely related to cardiac function, especially LV twist. Vector Flow Mapping (VFM) allows visualization of regional pressure distribution and noninvasive quantification of IVPD. The purpose of the present study was to investigate if and how IVPDs are related to LV twist in a model of acute heart failure (HF). Methods In 15 open-chest dogs, HF was induced by intracoronary injection of microspheres. The HF model was classified into two groups based on the LV end-diastolic pressure (LVEDP) (group1: LVEDP<18 mmHg (n=10), group2: LVEDP≥18 mmHg (n=8)). Color Doppler images from apical long-axis views were acquired at baseline and during HF. From these images, pressure differences (ΔP) were calculated along the LV inflow tract throughout the cardiac cycle. For the purpose of this study, the differences between apex and base during isovolumic relaxation time (ΔPIRT) and rapid early inflow period (ΔPE) were used for analyses. Furthermore, apical and basal short axis high frame rate 2D images were acquired, and peak rotation and peak twist were analyzed. Results LVEDP was 7±9, 14±2, 21±3 mmHg for baseline, group1 HF, and group2 HF, respectively. Pressure differences (both ΔPIRT and ΔPE) were visibly changed by the increase of LVEDP (Figure), and the magnitude of ΔPIRT, ΔPE and peak twist decreased significantly with the severity of heart failure. There were significant relationships between pressure differences (ΔPIRT and ΔPE) and dP/dtmin, tau, EF and peak twist (Table). In multivariate analyses, tau and peak twist were independent predictors for ΔPIRT and peak twist was independent predictor for ΔPE. Conclusion VFM analysis is feasible to noninvasively assess the IVPDs in acute heart failure. The IVPDs are closely related to the twisting motion of the LV, and reflect loss of apical suction during severe HF. FUNDunding Acknowledgement Type of funding sources: None. VFM images of pressure differences Correlations of pressure differences

scholarly journals In-vivo synthetic aperture and plane wave high frame rate cardiac imaging

2014 ◽  
Author(s):  
Matthias Bo Stuart ◽  
Jonas Jensen ◽  
Andreas Hjelm Brandt ◽  
Svetoslav Ivanov Nikolov ◽  
Michael Bachmann Nielsen ◽  
...  
Keyword(s):  
Plane Wave ◽  
Cardiac Imaging ◽  
Frame Rate ◽  
Synthetic Aperture ◽  
High Frame Rate
Sign in / Sign up

Export Citation Format

Share Document