Determining diffusion tensors using magnetic resonance tomography scanners

A magnetic resonance tomography scanner configured to determine a diffusion tensor of an examination object, the magnetic resonance tomography scanner comprising:

• a control unit;
• a field magnet configured to generate a B0 field;
• gradient coils and a gradient control configured to generate magnetic field gradients in all spatial directions;
• and
• a radio-frequency unit and antennas configured to transmit an excitation pulse and receive a spin signal from the examination object,
• wherein the magnetic resonance tomography scanner is configured to acquire a volume image of the examination object by imaging magnetic resonance tomography without diffusion encoding,
• wherein the control unit is configured to segment the volume image and to determine a diffusion-relevant first symmetry property of the examination object in a plane of symmetry,
• wherein the control unit is configured to determine a first symmetry group of volume elements of the examination object having the first symmetry property,
• wherein the magnetic resonance tomography scanner is configured to acquire a first image of a first component of the diffusion tensor in a first direction at a first angle to the plane of symmetry by imaging magnetic resonance tomography with diffusion encoding,
• wherein the magnetic resonance tomography scanner is configured to acquire a second image of a second component of the diffusion tensor in a second direction at a second angle to the plane of symmetry by the imaging magnetic resonance tomography with diffusion encoding, wherein a magnitude of the second angle differs from a magnitude of the first angle,
• wherein the control unit is configured to map the first components obtained in the first image and the second components obtained in the second image from a plurality of second volume elements of the first symmetry group onto a first volume element by symmetry mapping, wherein the symmetry mapping is dependent upon the plane of symmetry and respective positions of the first and second volume elements;
• and
• wherein the control unit is configured to determine a diffusion tensor of the first volume element of the first symmetry group of the examination object in the plane of symmetry.

A computer program product configured to be loaded directly into a processor of a programmable control unit, the computer program product having program code configured to, with the processor, cause the control unit to at least perform:

• acquire a volume image of an examination object by imaging magnetic resonance tomography without diffusion encoding;
• segment the volume image and determine a diffusion-relevant first symmetry property of the examination object in a plane of symmetry;
• determine a first symmetry group of volume elements of the examination object with the first symmetry property;
• acquire a first image of a first component of a diffusion tensor in a first direction at a first angle to the plane of symmetry by imaging magnetic resonance tomography with diffusion encoding;
• acquire a second image of a second component of the diffusion tensor in a second direction at a second angle to the plane of symmetry by the imaging magnetic resonance tomography with diffusion encoding, wherein a magnitude of the second angle differs from a magnitude of the first angle;
• map the first components obtained in the first image and the second components obtained in the second image from a plurality of second volume elements of the first symmetry group onto a first volume element by symmetry mapping, wherein the symmetry mapping is dependent upon the plane of symmetry and respective positions of the first and second volume elements;
• and
• determine the diffusion tensor of the first volume element of the first symmetry group of the examination object in the plane of symmetry.

A non-transitory computer-readable storage medium with electronically readable control information stored thereupon in a control unit of a magnetic resonance tomography scanner, the storage medium configured to:

• acquire a volume image of an examination object by imaging magnetic resonance tomography without diffusion encoding;
• segment the volume image and determine a diffusion-relevant first symmetry property of the examination object in a plane of symmetry;
• determine a first symmetry group of volume elements of the examination object with the first symmetry property;
• acquire a first image of a first component of a diffusion tensor in a first direction at a first angle to the plane of symmetry by imaging magnetic resonance tomography with diffusion encoding;
• acquire a second image of a second component of the diffusion tensor in a second direction at a second angle to the plane of symmetry by the imaging magnetic resonance tomography with diffusion encoding, wherein a magnitude of the second angle differs from a magnitude of the first angle;
• map the first components obtained in the first image and the second components obtained in the second image from a plurality of second volume elements of the first symmetry group onto a first volume element by symmetry mapping, wherein the symmetry mapping is dependent upon the plane of symmetry and respective positions of the first and second volume elements;
• and
• determine the diffusion tensor of the first volume element of the first symmetry group of the examination object in the plane of symmetry.