Characteristics of the left ventricular three-dimensional maximum principal strain using cardiac computed tomography: reference values from subjects with normal cardiac function

This study evaluated the characteristics of left ventricular maximum principal strain (LV-MPS) using cardiac CT in subjects with normal LV function. Of 973 subjects who underwent retrospective electrocardiogram-gated cardiac CT using a third-generation dual-source CT without beta-blocker administration, 31 subjects with preserved LV ejection fraction ≥ 55% assessed by echocardiography without coronary artery stenosis and cardiac pathology were retrospectively identified. CT images were reconstructed every 5% (0–95%) of the RR interval. LV-MPS and the time to peak (TTP) were analyzed using the 16-segment model and compared among three levels (base, mid, and apex) and among four regions (anterior, septum, inferior, and lateral) using the Steel–Dwass test. The intra- and inter-observer reproducibilities for LV-MPS were calculated using intraclass correlation coefficients (ICCs). The intra- and inter-observer ICCs (95% confidence interval) for peak LV-MPS were 0.96 (0.94–0.97) and 0.94 (0.92–0.96), respectively. The global peak LV-MPS (median, inter-quantile range) was 0.59 (0.55–0.72). The regional LV-MPS significantly increased in the order of the basal (0.54, 0.49–0.59), mid-LV (0.57, 0.53–0.65), and apex (0.68, 0.60–0.84) (p