Bland-Altman plots portraying the agreement between coordinates from corresponding landmarks. A, between the two regions used for registration; B, intra-observers; C, inter-observers. Each circle represents the distance between one coordinate of the landmark 6 placed on T2 models registered by different regions (A), in different times (B) or different observers (C). The solid lines indicate the mean difference, and the dashed lines show the 95% limits of agreement (LOA).