Magnetic resonance apparatus and method for operation thereof with actively controllable radio-frequency coil profiles

A magnetic resonance (MR) apparatus comprising:

• a single radio-frequency (RF) source;
• an MR data acquisition scanner comprising an RF radiator comprising a radiator circuit in electrical communication with said single RF source;
• a computer configured to operate said MR data acquisition scanner while an examination subject is situated in the MR data acquisition scanner during a total scan duration;
• said computer being configured to operate said RF radiator, at respectively different fillies during said total scan duration, to feed said RF radiator from said single RF source so as to radiate an RF field during each of said different times that excites nuclear spins in said examination subject so as to cause the excited nuclear spins to emit MR signals that are detected as said MR scan data;
• said computer being configured to operate said MR data acquisition scanner to alter a current flowing in said radiator circuit, during at least some of said different times, to cause said RF radiator to respectively radiate said RF fields as respective B1+ fields with different B1+ field profiles during said at least some of said respective times, thereby exciting all of said nuclear spins with at least one of said B1+ field profiles and exciting at least some of said nuclear spins with multiple, different B1+ field profiles;
• said computer being configured to operate said MR data acquisition scanner to detect said MR signals from said nuclear spins, each of said MR signals having a signal evolution;
• a memory comprising a plurality of precalculated signal evolutions respectively for different substances;
• a processor provided with said MR signals, said processor having access to said memory and being configured to compare the signal evolution of said MR signals to said precalculated signal evolutions to obtain a comparison result that identifies a substance that produced said MR signals;
• and
• said processor being configured to make an identification of said substance available in electronic form from said processor.