1. A method for registering two medical images of a subject, comprising: providing a first medical image and a second medical image to a computerized processor and, from said processor, accessing an electronic memory arrangement in which a first anatomical atlas and a second anatomical atlas are stored, said first anatomical atlas having at least two anatomical features in common with said second anatomical atlas; in said processor, comparing said first medical image with said first anatomical atlas to identify a plurality of first labels respectively relating to anatomical features in said first medical image; in said processor comparing said second medical image with said second anatomical atlas to identify a plurality of second labels respectively relating to anatomical features in said second medical image; in said processor, automatically calculating a value of a similarity metric, that represents a degree of similarity, between said first labels and said second labels; in said processor, bringing said first medical image and said second medical image into registration with each other based on the value of the similarity metric; in said processor, identifying a plurality of sets of first labels from among said plurality of first labels, wherein each of the plurality of sets of first labels contains a plurality of first labels; in said processor, identifying a plurality of sets of second labels from among said plurality of second labels, wherein each of the plurality of sets of second labels contains a plurality of second labels; wherein the number of first labels within the set of first labels is different from the number of second labels within the set of second labels; in said processor, identifying pairs of sets of labels, each pair of sets of labels comprising a set of said first labels and a set of said second labels; in said processor, calculating said value of said similarity metric between said set of first labels and said set of second labels in each said pair; and making the first medical image and the second medical image brought into registration with each other available at an output of said processor in electronic form, as a data file.