1. A magnetic resonance (MR) imaging or spectroscopy method in which a main magnetic field is generated in an object by a main magnet and superimposed magnetic fields and radiofrequency fields are generated according to an MR sequence for forming images or spectra, wherein object signals are acquired from the object with at least one object detector during execution of the MR sequence, additional data are acquired from at least one monitoring field probe positioned in the vicinity of and surrounding the object, during execution of the MR sequence, the additional data from the monitoring field probes are used for adjusting the MR sequence such as to account for imperfections in the magnetic field behavior in the object, and/or the additional data from the monitoring field probes are used in conjunction with the object signals for reconstruction of the images or spectra.