3D-display of medical objects derived from cross-sectional images has demonstrated its clinical usefulness in various applications such as surgery planning and recently also in diagnostic radiology. Instead of viewing sequences of images the region of interest can be looked at in its 3D-shape or at least as a cross-sectional image within the anatomical surroundings (fig, 1,2). This new way of viewing is certainly more natural and understandable than the conventional one. If we imagine that the invention of X-rays, CT or MR had not been made yet, would we not aim at an imaging modality which would deliver images as known from anatomy? So having the new 3D-imaging facilities the physicians might act in the future Hore like anatomists (with radiological eyes), A 3D-image, however, if generated from a single parameter (such as a Hounsfield value in CT) does not nearly have the information content of the anatomical reality. In addition, the capability of performing a dissection at the computer screen requires, that the program behind the screen is able to perform the corresponding anatomic segmentation, This means that the data structure on which the 'anatomist program' is working must contain more detailed information on the organs to be displayed,