METHOD AND DEVICE FOR RADIAL DATA ACQUISITION IN THREE-DIMENSIONAL K-SPACE IN AN MR MEASUREMENT FOR A MAGNETIC RESONANCE SYSTEM

• US 20110095762A1
• Filed: 10/26/2010
• Published: 04/28/2011
• Est. Priority Date: 10/26/2009
• Status: Active Grant

• Current Assignee: Siemens Healthineers AG (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Piccini, Davide, Zenge, Michael
• Granted Patent: US 8,648,594 B2
• Time in Patent Office: Days
• US Class Current: 324/312
• CPC Class Codes: G01R 33/4824 using a non-Cartesian trajectory
• CPC Class Codes: G01R 33/4826 in three dimensions
• CPC Class Codes: G01R 33/561 by reduction of the scanning time, i.e. fast acquiring systems, e.g. using echo-planar pulse sequences

Abstract

For radial data acquisition in three-dimensional k-space in an MR measurement for a magnetic resonance system, data in k-space are acquired along straight-line spokes. Each of the spokes is thereby defined by a point on a sphere and the center point of this sphere, wherein the center point corresponding to the center of k-space. The points are arranged on the sphere such that a distribution of the points obeys the spiral phyllotaxis, in particular the Fibonacci phyllotaxis.

Claims

1. A method for radial data acquisition of magnetic resonance data in three-dimensional k-space, comprising the steps of:

with a magnetic resonance data acquisition system comprising a memory into which acquired magnetic resonance data are entered in k-space, entering acquired magnetic resonance data in k-space in said memory along straight-line spokes, wherein k-space in said memory comprises a center of k-space;

defining each of said spokes in k-space in said memory by one point among a plurality of points on a sphere, and a center point of said sphere, said center point of said sphere coinciding with said center of k-space; and

in k-space in said memory, defining said points on said sphere in a distribution of said points that obeys the spiral phyllotaxis.

2. A method as claimed in claim 1 comprising arranging said points on said sphere in k-space with said distribution of said points obeying the Fibonacci phyllotaxis.

3. A method as claimed in claim 1 comprising arranging said points on said sphere according to the Voronoi diagram.

4. A method as claimed in claim 1 comprising arranging said points on said sphere by employing a contact pressure model.

5. A method as claimed in claim 1 comprising organizing said points in k-space with a number of said spokes that are processed for data acquisition being equal to N, and wherein each point on said sphere is defined by a polar angle and an azimuthal angle, and wherein said polar angle of an n-th spoke is formed dependent on a root selected from the group consisting of the root of n and the root of N.

6. A method as claimed in claim 5 wherein the polar angle of the n-th spoke is proportional to said root.

7. A method as claimed in claim 5 wherein the polar angle θ

_n of the n-th spoke is;

8. A method as claimed in claim 1 comprising organizing said points in k-space with a number of said spokes that are processed for data acquisition being equal to N, and wherein each point on said sphere is defined by a polar angle and an azimuthal angle, and wherein the azimuthal angle of an n-th spoke is formed dependent on at least one of n and the golden angle.

9. A method as claimed in claim 8 wherein the azimuthal angle of the n-th spoke is φ

_n and wherein the golden angle is ψ

;

Φ

_n=mod(n×

Ψ

,2×

π

).

10. A method as claimed in claim 8 comprising selecting the golden angle from the group consisting of the small golden angle and the large golden angle.

11. A method as claimed in claim 1 comprising organizing said points in k-space with a number of said spokes that are processed for data acquisition being equal to N, and wherein each point on said sphere is defined by a polar angle and an azimuthal angle, and wherein said polar angle of an n-th spoke is formed dependent on a root selected from the group consisting of the root of n and the root of N, and wherein the azimuthal angle of the n-th spoke is formed dependent on at least one of n and the golden angle.

12. A method as claimed in claim 1 comprising dividing said spokes into M sets, and associating a k-th spoke, a (k+M)-th spoke, a (k+2·

M)-th spoke respectively with a k-th of said M sets according to a predetermined order of said spokes, and acquiring said data in k-space initially along all spokes of a respective one of said M sets before acquiring the data for another of said M sets along said spokes.

13. A method as claimed in claim 12 comprising selecting N to be a Fibonacci number and selecting a further order for processing spokes of one of said M sets to correspond to said predetermined order.

14. A method as claimed in claim 12 comprising selecting an additional order in which spokes of one of said M sets are processed for data acquisition to make a distance between spokes that are processed in direct succession with respect to each other as small as possible.

15. A magnetic resonance system for radial data acquisition of magnetic resonance data in three-dimensional k-space, comprising the steps of:

a magnetic resonance data acquisition system comprising a memory into which acquired magnetic resonance data are entered in k-space;

a computerized control unit configured to operate said data acquisition system to enter acquired magnetic resonance data in k-space in said memory along straight-line spokes, wherein k-space in said memory comprises a center of k-space;

said memory being configured to define each of said spokes in k-space in said memory by one point among a plurality of points on a sphere, and a center point of said sphere, said center point of said sphere coinciding with said center of k-space; and

said memory being configured to define, in k-space in said memory, said points on said sphere in a distribution of said points that obeys the spiral phyllotaxis.

16. A system as claimed in claim 15 wherein said memory is configured with said points on said sphere in k-space with said distribution of said points obeying the Fibonacci phyllotaxis.

17. A system as claimed in claim 15 said memory is configured with said points on said sphere according to the Voronoi diagram.

18. A system as claimed in claim 15 said memory is configured with said points on said sphere by employing a contact pressure model.

19. A system as claimed in claim 15 said memory is configured with said points organized in k-space with a number of said spokes that are processed for data acquisition being equal to N, and wherein each point on said sphere is defined by a polar angle and an azimuthal angle, and wherein said polar angle of an n-th spoke is formed dependent on a root selected from the group consisting of the root of n and the root of N.

20. A system as claimed in claim 19 said memory is configured with the polar angle of the n-th spoke is proportional to said root.

21. A system as claimed in claim 19 said memory is configured with the polar angle θ

_n of the n-th spoke is;

22. A system as claimed in claim 15 said memory is configured with said points organized in k-space with a number of said spokes that are processed for data acquisition being equal to N, and wherein each point on said sphere is defined by a polar angle and an azimuthal angle, and wherein the azimuthal angle of an n-th spoke is formed dependent on at least one of n and the golden angle.

23. A system as claimed in claim 22 said memory is configured with the azimuthal angle of the n-th spoke is φ

_n and wherein the golden angle is ψ

;

Φ

_n=mod(n×

Ψ

,2×

π

).

24. A system as claimed in claim 22 said memory is configured with the golden angle selected from the group consisting of the small golden angle and the large golden angle.

25. A system as claimed in claim 15 said memory is configured with said points organized in k-space with a number of said spokes that are processed for data acquisition being equal to N, and wherein each point on said sphere is defined by a polar angle and an azimuthal angle, and wherein said polar angle of an n-th spoke is formed dependent on a root selected from the group consisting of the root of n and the root of N, and wherein the azimuthal angle of the n-th spoke is formed dependent on at least one of n and the golden angle.

26. A system as claimed in claim 15 said memory is configured with said spokes divided into M sets, and associating a k-th spoke, a (k+M)-th spoke, a (k+2·

M)-th spoke respectively with a k-th of said M sets according to a predetermined order of said spokes, and acquiring said data in k-space initially along all spokes of a respective one of said M sets before acquiring the data for another of said M sets along said spokes.

27. A system as claimed in claim 26 said memory is configured with N selected to be a Fibonacci number and with a further order for processing spokes of one of said M sets selected to correspond to said predetermined order.

28. A system as claimed in claim 26 said memory is configured with an additional order in which spokes of one of said M sets are processed for data acquisition being selected to make a distance between spokes that are processed in direct succession with respect to each other as small as possible.

29. A non-transitory computer-readable storage medium encoded with programming instructions loaded into a computerized control and evaluation system of a magnetic resonance system comprising a memory, said programming instructions causing said computerized control and evaluation to operate said magnetic resonance system to:

enter acquired magnetic resonance data are into k-space in said memory along straight-line spokes, wherein k-space in said memory comprises a center of k-space;

define each of said spokes in k-space in said memory by one point among a plurality of points on a sphere, and a center point of said sphere, said center point of said sphere coinciding with said center of k-space; and

in k-space in said memory, define said points on said sphere in a distribution of said points that obeys the spiral phyllotaxis.