Device and method for prospective correction for gradient pulse shape distortions in MRI imaging

A gradient system for a magnetic resonance examination system, the gradient system comprising:

• at least one gradient coil, when supplied with electrical current, configured to generate at least one selection gradient magnetic field for spatially selective excitation by transmitting selection gradient pulses,
• wherein the selection gradient field is a spatial read-encoding gradient field and/or a crusher gradient field and/or a slice selection gradient field and/or a slice refocusing gradient field and/or a gradient field spatially selective in one or multiple dimensions, and
• a gradient coil amplifier configured to supply the electrical current to the gradient coil,
• a current sensor system configured to sample an electrical current supplied to the gradient coil by the gradient coil amplifier,
• a controller configured to store a known input selection gradient pulse shape generated by a gradient waveform generator;
• wherein
• the gradient system is further configured to prospectively determine, prior to execution of a spatially selective excitation, an actual selection gradient pulse shape predicted for an imaging zone by applying a current to field modulation transfer function (CGMTF) to the sampled electrical current, wherein the controller determines a predicted deviation between the predicted actual selection gradient pulse shape and the stored known input selection gradient pulse shape;
• and
• wherein the magnetic resonance examination system compensates for the predicted deviation by modifying a radio-frequency excitation pulse shape based on the stored known input selection gradient pulse shape and the predicted deviation, the modified radio-frequency excitation pulse shape being emitted concurrently with the selection gradient pulse during spatially selective excitation;
• and
• wherein the CGMTF describes how the gradient coil is translating the input current into the actual gradient field.