Characterization and Quantification of Vortex Flow in the Human Left Ventricle by Contrast Echocardiography Using Vector Particle Image Velocimetry

Abstract

OBJECTIVES The aims of this study were to: 1) assess the feasibility of left ventricular (LV) vortex flow analysis using contrast echocardiography (CE); and 2) characterize and quantify LV vortex flow in normal subjects and patients with LV systolic dysfunction. BACKGROUND Vortices that form during LV filling have specific geometry and anatomical locations that are critical determinants of directed blood flow during ejection. Therefore, it is clinically relevant to assess the vortex flow patterns to better understand the LV function. METHODS Twenty-five patients (10 normal and 15 patients with abnormal LV systolic function) underwent CE with intravenous contrast agent, Definity (Bristol-Myers Squibb Medical Imaging, Inc., North Billerica, Massachusetts). The velocity vector and vorticity were estimated by particle image velocimetry. Average vortex parameters including vortex depth, transverse position, length, width, and sphericity index were measured. Vortex pulsatility parameters including relative strength, vortex relative strength, and vortex pulsation correlation were also estimated. RESULTS Vortex depth and vortex length were significantly lower in the abnormal LV function group (0.443 ± 0.04 vs. 0.482 ± 0.06, p < 0.05; 0.366 ± 0.06 vs. 0.467 ± 0.05, p < 0.01, respectively). Vortex width was greater (0.209 ± 0.05 vs. 0.128 ± 0.06, p < 0.01) and sphericity index was lower (1.86 ± 0.5 vs. 3.66 ± 0.6, p < 0.001) in the abnormal LV function group. Relative strength (1.13 ± 0.4 vs. 2.10 ± 0.8, p < 0.001), vortex relative strength (0.57 ± 0.2 vs. 1.19 ± 0.5, p < 0.001), and vortex pulsation correlation (0.63 ± 0.2 vs. 1.31 ± 0.5, p < 0.001) were significantly lower in the abnormal LV function group. CONCLUSIONS It was feasible to quantify LV vorticity arrangement by CE using particle image velocimetry in normal subjects and those with LV systolic dysfunction, and the vorticity imaging by CE may serve as a novel approach to depict vortex, the principal quantity to assess the flow structure.

Left Ventricular Fluid Mechanics: The Long Way from Theoretical Models to Clinical Applications

“…51 It was suggested that the asymmetric vortical arrangement is the fluid functional counterpart of the looped heart structure, which enhances the atrio-ventricular mechanical synergy and supports the conservation of momentum from the entry jet to the ejected flow. Vortex flow visualization were performed by Echo-PIV in the animal work done by Sengupta et al 84 during impaired electrical activation and by Hong et al 42 on patients with DCM where modifications in vortex characteristics were described. More recently, using the same method, quantitative assessment of the vortex alteration due to hypertrophic nonobstructive cardiomyopathy and pharmacological inotropic modulation was given.…”

Ultrasound imaging velocimetry with interleaved images for improved pulsatile arterial flow measurements: a new correction method, experimental and in vivo validation

“…Hence, the method produces instantaneous, two-dimensional velocity vector fields. UIV has been used to study flow in straight [23,24] and curved tubes [25], vessel phantoms [26] and vortex phantoms [27], and for preliminary in vivo investigations in healthy arteries [26,28 -30] and the heart [28,31].…”

Asymptotic Model of Fluid–Tissue Interaction for Mitral Valve Dynamics

“…9,10,16 It is believed that such vortices play a central role in the overall synchronicity of the beating heart, 25 and the quantification of the vorticity patterns has driven attempts to improve understanding of cardiac diseases. 12,14 The natural and apparently harmonious behavior of the flowing blood modifies in presence of a dysfunctional mitral valve (MV) or by the insertion of prosthetic ones. 21,28 In fact, the vortex formation process is intrinsically connected to the dynamics of the mitral leaflets while they interact with the blood crossing the valve during diastole.…”