Fig. 1

Bland–Altman analysis diagrams for the intra-observer repeatability test and the inter-observer reproducibility test for the two groups. The difference between the measurements (Difference) is plotted on the vertical axis and their mean is plotted on the horizontal axis (Mean). Despite the zero line, the middle horizontal dotted line represents the mean difference and the two horizontal lines, one above and the other below, represent the 95% limits of agreement. A Intra-observer repeatability for experimental group. B Intra-observer repeatability for control group. C Inter-observer reproducibility for experimental group. D Interobserver reproducibility for control group