1. A method for segmenting a body structure image data set produced from a medical imaging method, comprising: using a reference data set to define delineated body structures corresponding to the body structure image data set; and ascertaining an overall mapping function that substantially maps the reference data set onto the body structure image data set, wherein the overall mapping function comprises a portion that includes a dissection of the reference data set into a plurality of structural parts and the individual rearrangement of at least one structural part of the plurality of structural parts relative to at least one other structural part of the plurality of structural parts of the reference data set, and a portion that includes a mapping function that maps the dissected and rearranged plurality of parts onto corresponding parts of the body structure image data set.