Analysis of ventricular contraction by factorial phase imaging with equilibrium radionuclide angiography

Equilibrium radionuclide angiography (ERNA) imaging of the heart is used to visualize and quantify the cardiac function. Phase image analysis has been used for the localization of several conduction and contraction abnormalities and has been proposed to evaluate cardiac resynchronization therapy. The ventricular contraction has been described with indices like mean, standard deviation, mode, synchrony and entropy with Fourier phase imaging (FoPI). Factorial phase imaging (FaPI) has been used for wall motion abnormalities analysis and on a cardiac phantom, but not for synchrony quantification. In this paper a comparison of several indices obtained with FoPI and FaPI for a normal population is presented. These indices were computed inside regions corresponding to left ventricle, right ventricle and the total ventricular area. A set of ERNA images from 23 normal volunteers was analyzed. The comparison of indices was carried out by paired Student's t test with a significance level of (p<0.05). The results show significant differences among FoPI and FaPI on the analysis of ventricular contraction in normal individuals and consequently, on the quantification of the synchrony of contraction. The indices obtained from FaPI can be used to characterize a normal subject population for the evaluation of ventricular contraction synchrony.