Quantitative analysis of echocardiographic cine-loops using a 2D-strain algorithm in correlation with thallium-201 SPECT imaging

The aim of this study was to investigate the correlation between the regional left ventricular (LV) contractility, assessed by two-dimensional (2D)-strain echocardiographic images, and regional LV perfusion, determined by thallium-201 single photon emission computed tomography (SPECT) imaging. Forty-five hospitalized patients with suspected myocardial ischemia (32 males, mean age 69 +/- 12 years) have undergone both echocardiography and SPECT imaging on the same day. The echocardiographic data has been obtained in three apical views. The data for each view has been processed by the 2D-strain algorithm, to produce six peak systolic longitudinal strain measurements per view, one per segment. The resulting measurements have been compared with the corresponding regions within the SPECT bull's-eye map (at rest). In order to handle inaccuracies in the positioning of the echocardiographic transducer, the two datasets have undergone registration based on local correlation. The mean correlation coefficients between SPECT perfusion and peak systolic longitudinal strain for the apical long-axis, apical two-chamber, and apical four-chamber views were 0.55 +/- 0.36, 0.47 +/- 0.35, and 0.64 +/- 0.30 respectively (negative correlation coefficients have been considered as zero). The overall mean correlation coefficient was 0.56 +/- 0.34. The scatter graphs of the average values of perfusion and the strain values showed a nonlinear relation between the two parameters. The average correlation coefficient is comparable to the values reported for the correlation between the average LV function, based on visual analysis of echocardiographic imaging, and the average LV perfusion, based on SPECT imaging.