The present invention relates to a medical data processing method of transforming a representation of an anatomical structure of a patient in a first imaging modality into a representation of the anatomical structure in a second, other imaging modality, the method being constituted to be executed by a computer and comprising the following steps: acquiring first modality image data describing the first modality medical image containing the representation of the anatomical structure in the first imaging modality; acquiring atlas data describing a first modality atlas image describing a general structure of the anatomical structure in the first imaging modality, the atlas data containing information about the representation of the general structure in the second imaging modality; determining, based on the first modality image data and the atlas data, a first matching transformation between the first modality medical image and the first modality atlas image; determining, based on the first matching transformation and the first modality atlas image and the information about the representation of the general structure in the second imaging modality second modality, a second modality image representation of the first modality medical image.