Histograms of the shifts along × (LR), Y (SI), Z (AP) for the two matching modalities and corresponding scatterplots. Distributions of the shifts (in mm) along left-right (X) (a), supero-inferior (Y) (b), and antero-posterior (Z) (c) axes for the two matching modalities (B-match and T-match), along with the scatterplots of the corresponding shifts. Bell curves are computed using mean and standard deviation of the underlining variables. Dashed lines represent the bisectors. The scatterplots shown in Figure 1a (XT vs XB), Figure 1b (YT vs YB), and Figure 1c (ZT vs ZB), have correlation coefficients of 0.94, 0.74 and 0.78, respectively, all highly statistically significant (p-value < 0.001). Note that ZT tends to be larger than ZB, especially for larger values of ZB (Figure 1c).