1. A method for operating a magnetic resonance tomography apparatus comprising the steps of: defining a multi-contrast sequence for exciting nuclear spins in a slice of a subject; defining parameters characteristic of said sequence; obtaining raw data from said slice by executing said sequence, and from said raw data, generating a plurality of images of said slice having respectively different contrast; and selectively combining said images with respectively different contrast in an interactive, real-time contrast variation via a user interface to generate an image with an optimum contrast.