1. A method for processing of diagnostic image data, comprising: determining three-dimensional image information using an imaging medico-technical method, in which an examined volume is subdivided into a plurality of voxels and each voxel is allocated a measurement value; selecting, by an evaluation device, a subset of the voxels from at least some of the plurality of voxels, the measurement values associated with the selected voxels satisfying a specific relationship with at least one defined limit value; identifying at least one cohesive volume area within the selected subset of the voxels; determining a surface of the identified cohesive volume area; determining the distance between voxels within the cohesive volume area and the surface; identifying volume elements within the cohesive volume area, with each volume element including a central voxel whose distance from the surface represents a local maximum; determining a constriction within the cohesive volume area, which separates identified volume elements from one another; combining volume elements that are mutually adjacent to the constriction to form a larger sub-region within the cohesive volume area only if the depth of the constriction is less than a constriction limit value; and subdividing the determined image information into a plurality of data subsets, the constriction providing a boundary between the different data subsets.