Abstract 13990: Blood Flow and Vortex Formation Mapped in the Left Ventricular Short Axis Image by Echocardiographic Particle Image Velocimetry

Abstract

Background: Echocardiographic particle image velocimetry (Echo-PIV)enables visualizing blood flow and vortex formation inside the left ventricle (LV). Although intracardiac blood flow structure is three-dimensional by nature, characteristics of blood flow from the LV short axis view are unknown. The purpose of this study was to characterize blood flow and vortex formation in the LV short axis image by using Echo-PIV.

Methods: Echocardiographic contrast images of the LV short axis were acquired from 6 healthy dogs. Echo-PIV analysis was performed off-line by using commercially available software (FlowExpert2C, KATOKOKEN) and blood flow velocity vector, color-coded vorticity contour map (clockwise vorticity was indicated by blue color area and counter clockwise vorticity was indicated by red color area), and streamlines were superimposed on the two-dimensional LV short axis images at base level. Blood flow and vortex formation was characterized during one cardiac cycle.

Results: During isovolumic relaxation and early diastole, no obvious blood flow and vortex formation was observed (Figure 1-2). During late diastole, counter clockwise vortex formation (red color area in Figure 3) was observed at anterior LV cavity area in 5 of 6 dogs, which continued until the end of isovolumic contraction phase (Figure 4). During systole, velocity vector showed blood flow into LV outflow tract in all dogs (Figure 5-6).

Conclusion: Blood flow and vortex formations were well characterized in the LV short axis image by Echo PIV. Counter clockwise vortex in late diastole seems to lead spiral ejection flow. Echo PIV may play a key role in order to elucidate the blood flow structure inside the left ventricle.