Parallel MRI method using calibration scan, coil sensitivity maps and navigators for rigid motion compensation

Patent metadata

Field	Value
Publication number	US-10067213-B2
Application number	US-201113995378-A
Country	US
Kind code	B2
Filing date	Dec 16, 2011
Priority date	Dec 22, 2010
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

Magnetic resonance (MR) calibration data are acquired using a plurality of radio frequency receive coils, and both coil sensitivity maps and reference projection vectors are generated based on the MR calibration data. During imaging, extra navigator projection vectors are acquired, or part of the imaging data can be used as navigator projection vectors. Partially parallel imaging (PPI) can performed to enhance the navigation information. The navigator projection vectors and the reference projection vectors are sensitivity weighted using the coil sensitivity maps to generate navigator sensitivity weighted projection vectors (navigator SWPV) and reference sensitivity weighted projection vectors (reference SWPV) respectively, and these are compared to generate subject position information. The subject motions are compensated prospectively or retrospectively using the generated subject position information. The motion compensation may be prospective, performed by adjusting an imaging volume of the PPI based on the subject position information.

First claim

Having thus described the preferred embodiments, the invention is now claimed to be:

1. A method comprising:
acquiring magnetic resonance calibration data using a plurality of radio frequency receive coils;
generating coil sensitivity maps for the radio frequency receive coils based on the MR calibration data;
generating reference projection vectors based on the MR calibration data;
performing magnetic resonance imaging including acquiring magnetic resonance imaging data;
generating magnetic resonance navigator projection vectors based on a portion of the acquired magnetic resonance imaging data or extra data acquired with the magnetic resonance imaging data;
comparing the magnetic resonance navigator projection vectors with the reference projection vectors to generate subject position information; and
in the magnetic resonance imaging, compensating for subject motion prospectively or retrospectively using the generated subject position information.

2. The method as set forth in claim 1 , further comprising:
sensitivity weighting the magnetic resonance navigator projection vectors and the reference projection vectors using the coil sensitivity maps to generate magnetic resonance navigator sensitivity weighted projection vectors (navigator SWPV) and reference sensitivity weighted projection vectors (reference SWPV) respectively;
wherein the comparing comprises comparing the magnetic resonance navigator SWPV with the reference SWPV to generate the subject position information.

3. The method as set forth in claim 2 , wherein the comparing comprises:
computing cross correlations between the magnetic resonance navigator SWPV and the reference SWPV; and
generating the subject position information based on the computed cross correlations.

4. The method as set forth in claim 1 , wherein the comparing comprises:
computing cross correlations between the magnetic resonance navigator projection vectors and the reference projection vectors; and
generating the subject position information based on the computed cross correlations.

5. The method as set forth in claim 1 , wherein the magnetic resonance imaging comprises partially parallel imaging (PPI) selected from a group consisting of sensitivity encoding (SENSE), simultaneous acquisition off spatial harmonics (SMASH), generalized autocalibrating partially parallel acquisition (GRAPPA).

6. The method as set forth in claim 1 , further comprising: displaying the one or more reconstructed magnetic resonance images on a display device.

7. The method as set forth in claim 1 , wherein the one or more reconstructed magnetic resonance images comprise a time sequence of reconstructed magnetic resonance images and the method further comprises:
displaying a CINE sequence of the time sequence of reconstructed magnetic resonance images on a display device.

8. The method as set forth in claim 1 , wherein the compensating comprises:
performing prospective motion compensation by adjusting an imaging volume based on the generated subject position information.

9. The method as set forth in claim 1 , wherein the compensating comprises:
performing retrospective motion compensation based on the subject position information.

10. The method as set forth in claim 1 , wherein at least the generating of coil sensitivity maps, the generating of reference projection vectors, and the comparing of the magnetic resonance navigator projection vectors with the reference projection vectors are performed by a digital processor.

11. A method comprising:
acquiring magnetic resonance (MR) calibration data using a plurality of radio frequency receive coils;
generating coil sensitivity maps for the radio frequency receive coils based on the MR calibration data;
acquiring magnetic resonance navigator projection vectors and sensitivity weighting the acquired magnetic resonance navigator projection vectors using the coil sensitivity maps to generate navigator sensitivity weighted projection vectors (navigator SWPV);
performing magnetic resonance imaging;
generating subject position information based on the navigator SWPV; and
in the magnetic resonance imaging, compensating for subject motion prospectively or retrospectively using the generated subject position information.

12. The method as set forth in claim 11 , wherein the generating of subject position information comprises:
computing cross correlations between the navigator SWPV and reference projection vectors; and
generating the subject position information based on the computed cross correlations.

13. The method as set forth in claim 12 , further comprising:
sensitivity weighting the reference projection vectors using the coil sensitivity maps to generate reference sensitivity weighted projection vectors (reference SWPV);
wherein the computing cross correlations comprises computing cross correlations between the navigator SWPV and the reference SWPV.

14. The method as set forth in claim 12 , further comprising:
generating the reference projection vectors based on magnetic resonance data acquired prior to acquiring imaging data.

15. The method as set forth in claim 12 , further comprising:
generating the reference projection vectors based on the MR calibration data.

16. The method as set forth in claim 11 , wherein the magnetic resonance imaging comprises partially parallel imaging (PPI) selected from a group consisting of sensitivity encoding (SENSE), simultaneous acquisition off spatial harmonics (SMASH), generalized autocalibrating partially parallel acquisition (GRAPPA).

17. The method as set forth in claim 11 , further comprising:
displaying a motion-compensated reconstructed magnetic resonance image generated by the magnetic resonance imaging and compensating on a display device.

18. The method as set forth in claim 11 , wherein the compensating comprises:
performing prospective motion compensation by adjusting an imaging volume based on the generated subject position information.

19. The method as set forth in claim 11 , wherein at least the generating of coil sensitivity maps, the sensitivity weighting of the acquired magnetic resonance navigator projection vectors, and the generating of subject position information are performed by a digital processor.

20. An apparatus comprising:
a magnetic resonance (MR) scanner;
a plurality of radio frequency receive coils; and
a data processing device configured to cooperate with the MR scanner and the radio frequency receive coils to
acquire MR calibration data using the plurality of radio frequency receive coils;
generate coil sensitivity maps for the radio frequency receive coils based on the MR calibration data;
generating reference projection vectors based on the MR calibration data;
performing MR imaging including acquiring MR imaging data;
generating MR navigator projection vectors based on a portion of the acquired MR imaging data or extra data acquired with the MR imaging data;
comparing the MR navigator projection vectors with the reference projection vectors to generate subject position information; and
in the MR imaging, compensating for subject motion prospectively or retrospectively using the generated subject position information.

Assignees

• Huang Feng
• Lin Wei
• Koninklijke Philips Nv

Inventors

• Huang Feng
• Lin Wei

Classifications

• G01R33/58

  Calibration of imaging systems, e.g. using test probes {, Phantoms; Calibration objects or fiducial markers such as active or passive RF coils surrounding an MR active material} · CPC title

• G01R33/5611 Primary

  Parallel magnetic resonance imaging, e.g. sensitivity encoding [SENSE], simultaneous acquisition of spatial harmonics [SMASH], unaliasing by Fourier encoding of the overlaps using the temporal dimension [UNFOLD], k-t-broad-use linear acquisition speed-up technique [k-t-BLAST], k-t-SENSE (structural details of arrays of sub-coils G01R33/3415) · CPC title

• G01R33/5676

  Gating or triggering based on an MR signal, e.g. involving one or more navigator echoes for motion monitoring and correction · CPC title

• G01R33/56325

  Cine imaging · CPC title

• G01R33/56509 Primary

  due to motion, displacement or flow, e.g. gradient moment nulling (G01R33/567 takes precedence) · CPC title