Method for determining local deviations of a main magnetic field of a magnetic resonance device

A method for determining a local deviation of a main magnetic field of a magnetic resonance device, comprising:

• recording a first image data record of an examination region by the magnetic resonance device with a first frequency encoding gradient;
• recording a second image data record of the examination region by the magnetic resonance device with a second frequency encoding gradient being different from the first frequency encoding gradient;
• calculating a transformation displacement field based on the first and the second image data records;
• determining the local deviation of the main magnetic field from a setpoint value based on the calculated transformation displacement field;
• and
• displaying the calculated local deviation of the main magnetic field.

A computer program executed on a computer for determining a local deviation of a main magnetic field of a magnetic resonance device, comprising:

• a computer code that:
• calculates a transformation displacement field based on a first image data record and a second image data record of an examination region recorded by the magnetic resonance device with different frequency encoding gradients;
• and
• determines the local deviation of the main magnetic field from a setpoint value based on the calculated transformation displacement field.

A magnetic resonance unit, comprising:

• an image recording device that records a first image data record and a second image data record of an examination region with different frequency encoding gradients;
• and
• an image processing unit that:
• calculates a transformation displacement field based on the first and the second image data records, and
• determines the local deviation of the main magnetic field from a setpoint value based on the calculated transformation displacement field.