Fig. 1

Typical examples of 2D grayscale images in which the contour is manually corrected by the operators. a Due to a motion artifact, the automatically obtained contour was not tight around its original structure (a. II). The operators corrected this (a. III). In (b) a large cortical interruption with underlying trabecular bone loss is shown (b. I, arrow). The automatically obtained contour does not follow the outer margin of the original structure at the cortical interruption (b. II). The operators therefore corrected the contour (b. III)