Abstract 13216: Evaluation of Left Ventricular Flow Propagation Velocity From Multi-Dimensional Cardiac Imaging

Abstract

Introduction: The propagation velocity (Vp) during the left ventricular (LV) early diastole has been proposed as a marker of the diastolic function. However, the measurement of Vp is limited to one-dimensional data from Color M-mode (CMM) echocardiography and does not consider the spatiotemporal variation of Vp. Methods: We introduce a new method to evaluate the LV diastolic flow propagation from multi-dimensional cardiac flow imaging. The proposed method estimates the local and instantaneous flow propagation velocity (V prop ) by fitting the first order wave equation to the velocity gradients with weighted least-squares. The proposed method was validated using the synthetic vortex ring flow data. The method was applied to the LV flow data acquired with two-dimensional phase-contrast magnetic resonance imaging (pc-MRI) and 4D flow MRI. Results: The V prop estimated from multi-dimensional data has about 50% less error than the V prop from one-dimensional data. Fig. 1(a) shows the waveforms of the mitral inflow velocity, the IVPD, and the propagation intensity (I prop ) during the LV diastole of a normal filling patient. During early diastole, the timing of peak flow propagation coincides with the peak intraventricular pressure difference. Fig. 1(b) presents the fields of the blood flow velocity, the V prop , and the relative pressure from the timeframes indicated using the dotted lines in the waveform plots. The flow propagation towards the apex is mainly located at the front of the inflow jet and downstream of the vortex ring formed near mitral valve tips. Conclusions: This study introduces a novel propagation velocity measurement method for multi-dimensional cardiac flow imaging and demonstrated the V prop ’s spatial distribution temporal evolution.