Method and magnetic resonance system to reduce distortions in diffusion imaging

A magnetic resonance apparatus for reducing distortions in diffusion-weighted magnetic resonance images of an examination subject, comprising:

• a magnetic resonance data acquisition unit;
• a control unit that operates said magnetic resonance data acquisition unit to acquire magnetic resonance data in a first measurement with a first diffusion weighting;
• said control unit also operating said magnetic resonance data acquisition unit to acquire magnetic resonance data in a second measurement with a second diffusion weighting that is different from said first diffusion weighting;
• a computerized processor configured to automatically determine a non-linear, system-specific distortion-correcting function based on information that is specific to said magnetic resonance data acquisition system;
• said computerized processor being configured to calculate correction parameters, by applying said system-specific distortion-correcting function to said magnetic resonance data acquired in said first and second measurements, to distortion-correcting subsequently-acquired diffusion-weighted magnetic resonance images;
• and
• said control unit operating said magnetic resonance data acquisition unit to acquire a diffusion-weighted magnetic resonance image of the examination subject that embodies distortions therein, and said computerized processor being configured to apply said correction parameters to said diffusion-weighted magnetic resonance image to correct said diffusion-weighted magnetic resonance image to at least reduce said distortions therein.