Correction of distortions in diffusion-weighted magnetic resonance imaging

A magnetic resonance system for correcting image distortions occurring in diffusion-weighted magnetic resonance images obtained from an examination subject, comprising:

• a magnetic resonance data acquisition apparatus that acquires a reference image, without diffusion weighting, from an examination subject;
• said magnetic resonance data acquisition apparatus also acquiring a first diffusion-weighted image from the examination subject, said first diffusion-weighted image being acquired for a first diffusion direction and with a first diffusion weighting and a first diffusion gradient polarity;
• said magnetic resonance data acquisition apparatus also acquiring a second diffusion-weighted image from the subject for said first diffusion direction, and with at least one of a diffusion weighting that is different from said first diffusion weighting and a diffusion gradient polarity that is different from said first diffusion gradient polarity;
• and
• a computerized processor configured to determine a first set of deskewing parameters that deskew said first diffusion-weighted image, and a second set of deskewing parameters that deskews said second diffusion-weighted image and are correlated with said first set of deskewing parameters, by simultaneously minimizing differences between the first diffusion-weighted image, deskewed with first set of deskewing parameters, and the reference image and differences between the second diffusion-weighted image, deskewed with the second set of deskewing parameters, and the reference image.

A non-transitory computer-readable storage medium encoded with programming instructions, said storage medium being loadable into a computer system of a magnetic resonance apparatus and said programming instructions causing said computer system to:

• operate a magnetic resonance data acquisition apparatus to acquire a reference image, without diffusion weighting, from an examination subject;
• operate said magnetic resonance data acquisition apparatus to acquire a first diffusion-weighted image from the examination subject, said first diffusion-weighted image being acquired for a first diffusion direction and with a first diffusion weighting and a first diffusion gradient polarity;
• operate said magnetic resonance data acquisition apparatus to acquire a second diffusion-weighted image from the subject for said first diffusion direction, and with at least one of a diffusion weighting that is different from said first diffusion weighting and a diffusion gradient polarity that is different from said first diffusion gradient polarity;
• and
• determine a first set of deskewing parameters that deskew said first diffusion-weighted image, and a second set of deskewing parameters that deskews said second diffusion-weighted image and are correlated with said first set of deskewing parameters, by simultaneously minimizing differences between the first diffusion-weighted image, deskewed with first set of deskewing parameters, and the reference image and differences between the second diffusion-weighted image, deskewed with the second set of deskewing parameters, and the reference image.