Effect of through-plane and twisting motion on left ventricular strain calculation: direct comparison between two-dimensional and three-dimensional speckle-tracking echocardiography.

BACKGROUND: The aim of this study was to investigate the effect of out-of-plane motion on discrepancies in strain measurements between two-dimensional (2D) and three-dimensional (3D) echocardiography.

METHODS: Two-dimensional and 3D data sets were acquired in 54 patients. Using 2D and 3D speckle-tracking software, global circumferential strain (CS) and longitudinal strain (LS) as well as CS and LS at three left ventricular (LV) levels was measured. The effect of through-plane motion was assessed by mitral annular displacement.

RESULTS: Although a good correlation of global CS was noted between the two methods (r = 0.80, P < .01), mean values of global CS were significantly higher on 3D compared with 2D echocardiography. Correlations of CS and their mean differences were 0.65 and -4.61 at the basal level, 0.76 and -4.17 at the midventricular level, and 0.60 and -2.23 at the apical level, respectively. Correlation of global CS between the two methods was higher in patients who showed mitral annular displacement < 9.4 mm (r = 0.81) compared with those with mitral annular displacement ≥ 9.4 mm (r = 0.61). A good correlation of global LS (r = 0.89, P < .01) was noted, with no significant bias. Correlations of LS and their mean differences were 0.52 and 1.59 at the basal level, 0.89 and -1.17 at the midventricular level, and 0.73 and 1.46 at the apical level, respectively. Correlation of LS between the two methods was higher in patients who showed LV twist < 12.2° (r = 0.94) compared with patients with LV twist ≥ 12.2° (r = 0.68).

CONCLUSIONS: Through-plane motion produced discrepancies in CS measurements, especially at the LV basal level. Larger bias of LS at the basal and apical LV levels compared with the midventricular level between the two methods suggests that LV twisting also affects the calculation of 2D LS.