A method for facilitating comparison of image data from a given medical imaging protocol with archive image data, includes obtaining subject image data from a scan of a subject using the medical imaging protocol, obtaining archive image data differing from the subject image data in a given variable, determining a modifier usable to reduce the difference between the archive and subject image data, using the modifier to modify one of the subject image data and the archive image data to reduce the difference, and comparing the modified archive or subject image data with the subject or archive image data.