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 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 anatomically significant point and to the anatomically significant surface in each segmentation step; and 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.