Validation of Echodynamography in Comparison with Particle-image Velocimetry

Abstract

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.

A Review on Novel Channel Materials for Particle Image Velocimetry Measurements—Usability of Hydrogels in Cardiovascular Applications

“…Two studies, by Oktamuliani et al [ 65 ] and Shimizu and Ohta [ 66 ], presented hydrogels as a promising PIV channel material in cardiovascular research. Hydrogels can entirely replace standard materials such as silicon or PMMA.…”

“…The Scopus search revealed that only two studies performed cardiovascular PIV measurements using hydrogels as a channel material during the last 22 years. Oktamuliani et al [ 65 ] used PIV for visualizing flow velocity vectors based on a left ventricular phantom hydrogel. The phantom hydrogel was produced of PVA with a mixture of dimethyl sulfoxide (DMSO) and water.…”

“…It possessed transparency and formed a compliant material for pulsatile measurements. The research group also used an aqueous glycerin solution with an IOR of 1.5 as blood substitute [ 65 ]. The second study, from Shimizu and Ohta [ 66 ], examined changes in flow conditions due to plaque deformation in a stenotic vessel model.…”

Particle Image Velocimetry of 3D-Printed Anatomical Blood Vascular Models Affected by Atherosclerosis

“…Such models provide good results, but their preparation is time-consuming, and they are relatively expensive to produce. Hydrogel phantoms possess transparency and parameters that are required to work with imaging-based measurement systems [ 12 ]. A review of different kinds of hydrogel groups was completed by [ 13 ], outlining different advantages and disadvantages.…”

Colour-Doppler echocardiography flow field velocity reconstruction using a streamfunction–vorticity formulation

“…Echodynamography is one method developed for CD vector field estimation, which separates the flow into 'base' and divergence-free flows to reconstruct the velocity vector field [17]. Although the 'base' flow is arbitrary and only performs well for rotating flows [18], it has been validated against PIV and used in research [19,20]. Pedrizzetti & Tonti introduced an alternative method using the irrotational flow assumption [21], but this formulation underestimates the strength of rotating flows [18].…”