Correction of imaging methods in a magnetic resonance device
In a method, by a magnetic resonance device, a transmit B 1 field map is determined for a region, a plurality of MR images of at least one part of the region are acquired using transmitter settings differing from each other, and signal intensities of individual pixels measured by the MR images are interpolated by the transmit B 1 field map. A correction of the signal intensities may also be effected by carrying out a receive B 1 correction by a spatial mirroring of the transmit B 1 field map on a symmetry plane of a measured object. A magnetic resonance device is used to carry out the method. The method may be applied, for example, in medical diagnostics.
1. A method, using a magnetic resonance (MR) device, comprising:
determining a transmit B 1 field map for a region;
acquiring, by the MR device, a plurality of MR images of at least one part of the region, each MR image of the plurality of MR images being acquired using transmitter settings differing from transmitter settings used to acquire another MR image of the plurality of MR images;
interpolating signal intensities of pixels of the plurality of MR images using the transmit B 1 field map;
generating a resultant MR image based on the interpolation of the signal intensities of the pixels,
wherein a receive-side B 1 correction is carried out by a spatial mirroring of the transmit B 1 field map on a symmetry plane of a measured object.
2. The method as claimed in claim 1 , wherein the transmitter settings differ by virtue of differing transmitter scalings.
3. The method as claimed in claim 2 , wherein at least two differing transmitter voltages lie above and beneath a reference transmitter voltage.
4. The method as claimed in claim 3 , wherein the at least two differing transmitter voltages lie above and beneath the reference transmitter voltage through the use of transmitter scalings that result in flip angles that are less than or greater than the target flip angle.
5. The method as claimed in claim 1 , wherein the measured signal intensities of individual pixels are interpolated linearly.
6. The method as claimed in claim 1 , wherein the measured signal intensities of individual pixels are interpolated quadratically.
7. The method as claimed in claim 6 , wherein the interpolation is carried out on the basis of a logarithmic scale.
8. The method as claimed in claim 1 , wherein the measured intensities of individual pixels are interpolated by a weighted sum, wherein associated weighting factors are calculated from the transmit B 1 field map at a location of a pixel and differing transmitter scalings, and wherein a location-dependent noise increase factor is calculated from the associated weighting factors.
9. The method as claimed in claim 1 , wherein a movement correction is carried out on at least one MR image.
10. The method as claimed in claim 1 , wherein a parallel imaging is carried out.
11. The method as claimed in claim 1 , wherein a plurality of interpolations having different target B 1 values is carried out from a plurality of MR images having differing transmitter scalings.
12. The method as claimed in claim 1 , wherein a sign-sensitive interpolation, a phase-sensitive interpolation, or the sign-sensitive and the phase-sensitive interpolation are carried out.
13. The method as claimed in claim 1 , wherein a receive-side B 1 correction is carried out by a receive B 1 field map ascertained through a numeric field simulation.
14. A system comprising:
a magnetic resonance device configured to:
determine a transmit B 1 field map for a region;
acquire a plurality of MR images of at least one part of the region, each MR image of the plurality of MR images being acquired using transmitter settings differing from transmitter settings used to acquire another MR image of the plurality of MR images;
interpolate signal intensities of pixels of the plurality of MR images using the transmit B 1 field map; and
generate a resultant MR image based on the interpolation of the signal intensities of the pixels,
wherein a receive-side B 1 correction is carried out by a spatial mirroring of the transmit B 1 field map on a symmetry plane of a measured object.
15. The system of claim 14 , wherein the measured intensities of individual pixels are interpolated by a weighted sum,
wherein associated weighting factors are calculated from the transmit B 1 field map at a location of a pixel and differing transmitter scalings, and
wherein a location-dependent noise increase factor is calculated from the associated weighting factors.