* P <0.05.

Figures and legends

Figure 1. Echocardiographic and schematic images of the angle (*) measurement in the double aortic arch with 51.35°(A) and right aortic arch with mirror-image branches with 85.76°(B). LAA: left aortic arch; RAA: right aortic arch; DA: ductus arteriosus; MB: mirror-image branches; Sp.: spine.

Figure 2. Scatter plot of the angles in the double aortic arch and right aortic arch with mirror-image branches

Figure 3. ROC curve： The area under ROC was 0.9853 (95% CI was 0.9609 to 1.010). When the cut-off value was greater than 62.8°, the sensitivity was 95.5%, 95% CI: 77.2% - 99.9; the specificity was 96.9%, 95% CI: 89.3% - 99.6%.

Figure. 4 Bland-Altman plots showing the intra- (a) and inter- (b) observer variability for the angle measurements.