Figure 19b. Figures 18, 19. (18) Three-dimensional display–guided extraction of an oblique section from CT data obtained in a patient with a craniofacial disorder. A plane is selected interactively by means of the 3D display to indicate the orientation of the section plane (left). The section corresponding to the oblique plane is shown on the right. (19) Pseudocolor display. (a) Head MR imaging sections obtained at different times are displayed in green and red, respectively. Where there is a match, the composite image appears yellow. Green and red areas indicate regions of mismatch. (b) On the same composite image displayed after 3D scene-based registration, green and red areas indicate either a registration error or a change in an object (eg, a lesion) over the time interval between the two acquisitions.