Abstract: A system and method are disclosed for presenting projection image information, including a first image generating module or step, for generating a first image representing a first projection of a three-dimensional object; a second image generating module or step, for generating a second image representing a second projection of the three-dimensional object; an image display module or step, for displaying the first and second images; a region selection module or step, for selecting a first region in the first image; a correspondence module or step, for determining a second region in the second image that corresponds to the first region; and a marking module or step, for displaying a first mark on the first image to identify the first region, and a second mark on the second image to identify the corresponding second region.