1. A method for segmenting anatomical structures from 3D image data, the method comprising: setting a starting point in the 3D image data; identifying at least one of at least one known anatomically significant point and at least one known anatomically significant surface in the 3D image data; segmenting, proceeding from the starting point, the anatomical structure pixel by pixel with a multiplicity of segmentation steps such that an instantaneous distance is determined automatically relative to at least one of the at least one known anatomically significant point and to the at least one known anatomically significant surface in each segmentation step; establishing at least one of segmentation parameters and a selection of adjacent pixels for continuing the segmentation as a function of the determined distance, taking account of a model topology; and displaying a result of the segmentation process, wherein when a truncation point during the segmentation process is reached at a position at which the anatomical structure should not be truncated, based on the model topology, a search algorithm searches for pixels and continues the segmentation of the anatomical structure in an image region determined by an extrapolation of the already segmented anatomical structure, and wherein a gap in the segmented anatomical structure is filled up by means of interpolation.