Magnetic resonance tomographs are imaging devices that, for imaging an examination object, orient nuclear spins of the examination object using a strong external magnetic field and excite the spins to precession around this orientation by way of a magnetic alternating field. The precession or return of the spins from this excited state into a state with lower energy in turn generates a magnetic alternating field, also called a magnetic resonance signal, as a response, which is received by antennae.
With the aid of magnetic gradient fields, a spatial encoding is impressed on the signals, and this subsequently enables allocation of the received signal to a volume element. The received signal is then evaluated, and a three-dimensional representation of the examination object supplied.
The representation that is generated indicates a spatial density distribution of the spins.
Acquisition of the data for a large number of volume elements requires a considerable amount of time, which is often significantly longer than typical physiological processes such as beating of the heart or respiration. There are therefore magnetic resonance tomographs that acquire physiological measured values such as pulse or breathing by way of sensors to synchronize the image data acquisition by magnetic resonance with the physiological processes, so that, for example, data from a two-dimensional volume slice of the examination object is acquired during a pause in breathing, a further volume slice is acquired during the next pause in breathing and so on.
Document DE 10 2014 210 471 A1 describes a method for carrying out a magnetic resonance examination with a prospective movement correction.
From document DE 10 2015 205 937 A1 a method is known for simultaneously acquiring physiological signals and image data of a volume portion of an examination object.
For the safety of the patient, control of a magnetic resonance tomograph requires precise checking and certifying of the individual examination processes, so that only the most important fundamental examinations are covered by image data acquisition of this kind that is controlled by physiological signals.