Fig. 3

Bland–Altman plot comparison between manual and automated alpha angle measurement. All alpha angle measurements in the seven radial imaging planes were considered in the evaluations. The x-axis displays the average alpha angle of the two measurement techniques. The y-axis illustrates the difference in the alpha angle measurements between the two measurement instruments (manual–automated). The three dashed lines display the average difference in alpha angles, the upper and the lower limit of agreement for the average difference between the manual and automated alpha angle measurement. The limits of agreement spread were considerably larger for observer 1 (1st—31.8–40.5; 2nd—32.6–35.6) than for observer 2 (1st—27.3–21.9; 2nd—28.6–19.7)