Multiplane Scanning Stereo PIV for Biofluid Applications

The aim of this project is to map the 3D intracardiac spatiotemporal structure flow by mean phase-locked Stereo-PIV. The developed setup permits the flow field measurment in the whole left ventricle model without repeating the complex stereo calibration. It consisted of coupling Stereo-PIV apparatus and cardiovascular simulator system

Experimental Investigation of 3D Left Ventricular Flow Using a Novel Multiplane Scanning Stereo PIV Setup

The aim of this project is to design and develop a novel system that allows to quantitatively study the flow in experimental in vitro PIV models, for instance vascular segments, heart valves and left ventricle replicas. In this study we present an application which permits 3D volume reconstruction of the flow field by means of phase-locked stereo-PIV in a transparent pulsatile LV membrane model

A Novel Multiplane Scanning Stereo PIV Setup to Investigate Left Ventricular Flow

The spatiotemporal characteristics of the intraventricular flow field, and their evolution with time, are of (patho)physiological and clinical interest. This is shown in several recent in vivo studies, using modern medical imaging techniques. Intraventricular flow is also topic of biofluid mechanic research, in silico and in vitro. Particle image velocimetry (PIV) studies have been performed in hydraulic bench models to investigate the flow field inside a left ventricle (LV) replica in a two-dimensions. However, as the intraventricular flow has a complex 3D and unsteady structure. In this study therefore we present a novel experimental setup which allows 3D volume reconstruction of the flow field in a transparent pulsatile LV membrane model, in different controllable and repeatable physiological relevant hydrodynamic conditions. The setup was primarily designed and developed to facilitate consecutive stereoscopic measurements without repeating the complex and time consuming stereo calibration

4D Flow Patterns and Relative Pressure Distribution in a Left Ventricle Model by Shake-the-Box and Proper Orthogonal Decomposition Analysis

Purpose: Intraventricular blood flow dynamics are associated with cardiac function. Accurate, noninvasive, and easy assessments of hemodynamic quantities (such as velocity, vortex, and pressure) could be an important addition to the clinical diagnosis and treatment of heart diseases. However, the complex time-varying flow brings many challenges to the existing noninvasive image-based hemodynamic assessments. The development of reliable techniques and analysis tools is essential for the application of hemodynamic biomarkers in clinical practice. Methods: In this study, a time-resolved particle tracking method, Shake-the-Box, was applied to reconstruct the flow in a realistic left ventricle (LV) silicone model with biological valves. Based on the obtained velocity, 4D pressure field was calculated using a Poisson equation-based pressure solver. Furthermore, flow analysis by proper orthogonal decomposition (POD) of the 4D velocity field has been performed. Results: As a result of the Shake-the-Box algorithm, we have extracted: (i) particle positions, (ii) particle tracks, and finally, (iii) 4D velocity fields. From the latter, the temporal evolution of the 3D pressure field during the full cardiac cycle was obtained. The obtained maximal pressure difference extracted along the base-to-apex was about 2.7 mmHg, which is in good agreement with those reported in vivo. The POD analysis results showed a clear picture of different scale of vortices in the pulsatile LV flow, together with their time-varying information and corresponding kinetic energy content. To reconstruct 95% of the kinetic energy of the LV flow, only the first six POD modes would be required, leading to significant data reduction. Conclusions: This work demonstrated Shake-the-Box is a promising technique to accurately reconstruct the left ventricle flow field in vitro. The good spatial and temporal resolutions of the velocity measurements enabled a 4D reconstruction of the pressure field in the left ventricle. The application of POD analysis showed its potential in reducing the complexity of the high-resolution left ventricle flow measurements. For future work, image analysis, multi-modality flow assessments, and the development of new flow-derived biomarkers can benefit from fast and data-reducing POD analysis.</p

Bijdrage tot de speciale psychologie von het Joodsche volk

Groningen, Univ., Diss., 1919Julius Leydesdorf

Validation of 4D MRI flow and 4D echo-PIV using tomographic PIV in a left ventricle phantom

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