Differences between 3D-echocardiographic and MSCT-derived phantom volumes. Upper panel: Differences between true phantom volumes and the volumes measured by 3-D echocardiography and MSCT-CardIQ software. Mean differences for the respective methods are indicated. Lower panel: Bland-Altman plot of differences between phantom volumes measured by 3-D echocardiography and MSCT-CardIQ software against the average phantom volumes by the two methods. The mean difference and 95% confidence intervals for the mean difference ± 2SD are indicated.