Controlling magnetic resonance systems

Patent metadata

Field	Value
Publication number	US-10416258-B2
Application number	US-201313856231-A
Country	US
Kind code	B2
Filing date	Apr 3, 2013
Priority date	Apr 5, 2012
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

A method for controlling a magnetic resonance system outputs a pulse sequence including a first slice-selective excitation pulse that excites a first slice with a first magnetization. The pulse sequence includes a second slice-selective excitation pulse that excites a second slice with the first magnetization and a third slice-selective excitation pulse that excites the first slice with a second magnetization that cancels the first magnetization. The pulse sequence also includes and a fourth slice-selective excitation pulse that excites the second slice with a magnetization that cancels the first magnetization. The first slice and the second slice intersect.

First claim

The invention claimed is:

1. A method configured for controlling a magnetic resonance system, the method comprising:
outputting, by a processor, a pulse sequence for the magnetic resonance system;
wherein the pulse sequence comprises:
a first slice-selective excitation pulse configured to excite a first slice with a first magnetization;
a second slice-selective excitation pulse configured to excite a second slice with a second magnetization, wherein the first slice and the second slice intersect, and wherein the second magnetization is configured such that the second magnetization has substantially no effect on the first magnetization while exciting the second slice including an intersection between the first slice and the second slice;
a third slice-selective excitation pulse configured to excite the first slice with a third magnetization that substantially cancels the first magnetization; and
a fourth slice-selective excitation pulse configured to excite the second slice with a fourth magnetization that substantially cancels the second magnetization, such that a measurement volume is substantially constricted to the intersection between the first slice and the second slice with the application of the first slice-selective excitation pulse, the second slice-selective excitation pulse, the third slice-selective excitation pulse, and the fourth slice-selective excitation pulse.

2. The method of claim 1 , wherein each slice-selective excitation pulse of the first slice-selective excitation pulse, the second slice-selective excitation pulse, the third slice-selective excitation pulse, and the fourth slice-selective excitation pulse comprises a high-frequency pulse and a gradient signal, wherein a shape of the high-frequency pulse predefines a slice thickness of an excited slice and a delimitation accuracy between the excited slice and a non-excited area, and wherein the gradient signal predefines a slice plane.

3. The method of claim 2 , wherein the high-frequency pulse comprises a sine pulse.

4. The method of claim 1 , wherein the pulse sequence further comprises a refocusing pulse output for a third slice, wherein the third slice intersects with the first slice and the second slice.

5. The method of claim 2 , wherein the pulse sequence further comprises a refocusing pulse output for a third slice, wherein the third slice intersects with the first slice and the second slice.

6. The method of claim 3 , wherein the pulse sequence further comprises a refocusing pulse output for a third slice, wherein the third slice intersects with the first slice and the second slice.

7. The method of claim 4 , wherein each slice-selective excitation pulse of the first slice-selective excitation pulse, the second slice-selective excitation pulse, the third slice-selective excitation pulse, and the fourth slice-selective excitation pulse comprises a high-frequency pulse, the high frequency pulse having an amplitude and a phase optimized such that, after the pulse sequence is output, any difference between overall excited magnetization and magnetization in an area of intersection of the first slice and the second slice, or of the first slice, the second slice, and the third slice, is minimized.

8. The method of claim 5 , wherein each slice-selective excitation pulse of the first slice-selective excitation pulse, the second slice-selective excitation pulse, the third slice-selective excitation pulse, and the fourth slice-selective excitation pulse comprises a high-frequency pulse, the high frequency pulse having an amplitude and a phase optimized such that, after the pulse sequence is output, any difference between overall excited magnetization and magnetization in an area of intersection of the first slice and the second slice, or of the first slice, the second slice, and the third slice, is minimized.

9. The method of claim 6 , wherein each slice-selective excitation pulse of the first slice-selective excitation pulse, the second slice-selective excitation pulse, the third slice-selective excitation pulse, and the fourth slice-selective excitation pulse comprises a high-frequency pulse, the high frequency pulse having an amplitude and a phase optimized such that, after the pulse sequence is output, any difference between overall excited magnetization and magnetization in an area of intersection of the first slice and the second slice, or of the first slice, the second slice, and the third slice, is minimized.

10. The method of claim 7 , further comprising determining an actual distribution of a B 1 field, the determining preceding the optimization of the amplitude and the phase, and wherein the optimization takes the B 1 distribution into account.

11. The method of claim 8 , further comprising determining an actual distribution of a B 1 field, the determining preceding the optimization of the amplitude and the phase, and wherein the optimization takes the B 1 distribution into account.

12. The method of claim 9 , further comprising determining an actual distribution of a B 1 field, the determining preceding the optimization of the amplitude and the phase, and wherein the optimization takes the B 1 distribution into account.

13. The method of claim 7 , further comprising determining an actual distribution of a Bo field, the determining preceding the optimization of the amplitude and the phase, and wherein the optimization takes the Bo distribution into account.

14. The method of claim 8 , further comprising determining an actual distribution of a Bo field, the determining preceding the optimization of the amplitude and the phase, and wherein the optimization takes the Bo distribution into account.

15. The method of claim 9 , further comprising determining an actual distribution of a Bo field, the determining preceding the optimization of the amplitude and the phase, and wherein the optimization takes the Bo distribution into account.

16. The method of claim 10 , further comprising determining an actual distribution of a Bo field, the determining preceding the optimization of the amplitude and the phase, and wherein the optimization takes the Bo distribution into account.

17. The method of claim 11 , further comprising determining an actual distribution of a Bo field, the determining preceding the optimization of the amplitude and the phase, and wherein the optimization takes the Bo distribution into account.

18. The method of claim 12 , further comprising determining an actual distribution of a Bo field, the determining preceding the optimization of the amplitude and the phase, and wherein the optimization takes the Bo distribution into account.

19. The method of claim 1 , wherein the magnetic resonance system comprises a transmitting antenna arrangement, the transmitting antenna arrangement comprising a plurality of independent high-frequency transmission channels, wherein at least two high-frequency transmission channels of the plurality of independent high-frequency transmission channels are operable to output independent pulse sequences in parallel, and wherein the independent pulse sequences each comprise the first slice-selective excitation pulse, the second slice-selective excitation pulse, the third slice-selective excitation pulse and the fourth slice-selective excitation pulse.

20. A control device configured for controlling a magnetic resonance system, the magnetic resonance system comprising one or more high-frequency transmission channels, wherein:
the control device is coupled with at least one of the one or more high-frequency tran

Assignees

• Fautz Hans Peter
• Gumbrecht Rene
• Siemens Ag

Inventors

• Fautz Hans Peter
• Gumbrecht Rene

Classifications

• G01R33/5659

  caused by a distortion of the RF magnetic field, e.g. spatial inhomogeneities of the RF magnetic field (G01R33/56509, G01R33/56518, G01R33/56536 take precedence) · CPC title

• G01R33/4836

  using an RF pulse being spatially selective in more than one spatial dimension, e.g. a 2D pencil-beam excitation pulse · CPC title

• G01R33/4833 Primary

  using spatially selective excitation of the volume of interest, e.g. selecting non-orthogonal or inclined slices · CPC title

• G01R33/3415

  comprising arrays of sub-coils {, i.e. phased-array coils with flexible receiver channels} · CPC title

• G01R33/54

  Signal processing systems, e.g. using pulse sequences {; Generation or control of pulse sequences; Operator console} · CPC title