System and method for providing real-time motion correction by utilizing navigators

• US 6,771,068 B2
• Filed: 05/10/2001
• Issued: 08/03/2004
• Est. Priority Date: 05/10/2001
• Status: Active Grant

• Current Assignee: The General Hospital Corporation (Mass General Brigham, Inc.)
• Original Assignee: The General Hospital Corporation (Mass General Brigham, Inc.)
• Inventors: Dale, Anders M., Van Der Kouwe, André J. W.
• Primary Examiner(s): ARANA, LOUIS M
• Application Number:
  US09/853,011
• Publication Number:
  US 20020180436A1
• Time in Patent Office: 1,181 Days
• Field of Search: 324/307, 324/309, 324/306, 324/312, 324/314, 324/300, 324/318, 324/322
• US Class Current: 324/307
• CPC Class Codes: G01R 33/56509 due to motion, displacement or flow, e.g. gradient moment nulling G01R33/567 takes precedence

Abstract

A method and system of correcting for a motion of an object are provided. In these system and method, the navigator data and map data are first obtained for the object. Then, the navigator data is compared with the map data to generate comparison data. Thereafter, a translation and/or a rotation of the object is corrected in real time as a function of the comparison data. The navigator can be preferably an octant navigator. In one exemplary embodiment, a scanning sequence can be used to determine a position of the object. This scanning sequence may include a signal portion which includes at least one radio frequency signal, an octant navigator portion which includes at least one octant navigator, and a spoiler portion provided for reducing a signal magnitude of the scanning sequence. The octant navigator is provided for allowing a measurement of at least one of the rotation and translation of the object. The navigator portion is advantageously provided between the signal portion and the spoiler portion.

Claims

1. A method of correcting for a motion of an object, comprising the steps of:

a) obtaining navigator data for the object;

b) obtaining map data for the object;

c) comparing the navigator data with the map data to generate comparison data; and

d) correcting at least one of a translation and a rotation of the object in real time as a function of the comparison data.

2. The method according to claim 1, further comprising the step of:

e) scanning the object during the performance of step (d).

3. The method according to claim 1, further comprising the step of:

f) prior to step (a), obtaining k-space data of k-space which corresponds to positional data for the object.

4. The method according to claim 3, wherein step (a) includes the substep of determining at least one effective value of the navigator data.

5. The method according to claim 4, wherein the value includes at least one of an effective radius and effective angles for the k-space.

6. The method according to claim 5, wherein the effective radius is selected based on at least one of the following:

i. an amount of energy in the k-space present at a particular radius,

ii. the size of the particular radius, and

iii. a non-periodic characteristic of an information structure provided at the particular radius.

7. The method according to claim 6, wherein the energy at the effective radius is capable of providing a measurable signal.

8. The method according to claim 6, wherein the size of the effective radius facilitates a generation of an acceptable angular resolution.

9. The method according to claim 6, wherein the information structure is usable to uniquely match an acceptable range of rotations.

10. The method according to claim 3, wherein step (b) includes the substep of generating the map data as a function of the navigator data.

11. The method according to claim 10, where the navigator data includes a navigator having a path which is three dimensional.

12. The method according to claim 11, wherein the path may lie within the surface of a sphere.

13. The method according to claim 10, where the navigator data includes a navigator which gauges a full rigid-body motion in a single read.

14. The method according to claim 10, wherein the octant navigator is a navigator which traces at least a path in the k-space, the path circumscribing an octant on a substantially spherical surface in the k-space.

15. The method according to claim 10, wherein the navigator data includes data for an octant navigator.

16. The method according to claim 15, wherein the octant navigator provides data to describe at least one of the rotation and the translation of the object on the surface of the k-space.

17. The method according to claim 15, wherein the octant navigator includes a plurality of gradients.

18. The method according to claim 17, further comprising the step of:

g) obtaining further navigator data which includes data for a further octant navigator, the further octant navigator including the gradients, wherein step (d) includes the substep of correcting the gradients of the further octant navigator based on a comparison of the data for the octant navigator and the map data.

19. The method according to claim 18, wherein steps (a) through (g) are performed for each slice of the k-space for the object, and wherein the gradients of the further octant navigator are corrected for each slice.

20. The method according to claim 1, wherein step (d) further comprises the substep of modifying the map data as a function of the comparison data.

21. The method according to claim 1, wherein the object is an anatomical structure, and further comprising the step of:

h) repeating steps (a) through (d) for a predetermined time period to complete a scan of the anatomical structure.

22. The method according to claim 21, wherein step (b) is performed as an initial step of the scan.

23. The method according to claim 1, wherein the navigator data includes data for an octant navigator, and wherein step (a) includes the substep of obtaining a scanning sequence which includes a signal portion, a spoiler portion and a navigator portion for the octant navigator, the navigator portion being provided between the signal portion and the spoiler portion.

24. A method of correcting for a motion of an object, comprising the steps of:

a) obtaining data of an octant navigator for the object;

b) obtaining map data for the object;

c) comparing the data of the octant navigator with the map data to generate comparison data; and

d) correcting at least one of a translation and a rotation of the object as a function of the comparison data.

25. The method according to claim 24, wherein step (d) is performed in real time, and further comprising the step of:

e) scanning the object during the performance of step (d).

26. The method according to claim 24, further comprising the step of:

f) prior to step (a), obtaining k-space data of k-space which corresponds to positional data for the object.

27. The method according to claim 26, wherein step (a) includes the substep of determining at least one effective value of the navigator data.

28. The method according to claim 27, wherein the value includes at least one of an effective radius and effective angles for the k-space.

29. The method according to claim 28, wherein the effective radius is selected based on at least one of the following:

i. an amount of energy in the k-space present at a particular radius,

ii. the size of the particular radius, and

iii. a non-periodic characteristic of an information structure provided at the particular radius.

30. The method according to claim 29, wherein the energy at the effective radius is capable of providing a measurable signal.

31. The method according to claim 29, wherein the size of the effective radius facilitates a generation of an acceptable angular resolution.

32. The method according to claim 29, wherein the information structure is usable to uniquely match an acceptable range of rotations.

33. The method according to claim 26, wherein step (b) includes the substep of generating the map data as a function of the navigator data.

34. The method according to claim 24, wherein the octant navigator is a navigator which traces at least a path in the k-space, the path circumscribing an octant on a substantially spherical surface in the k-space.

35. The method according to claim 24, where the navigator data includes a navigator which gauges a full rigid-body motion in a single read.

36. The method according to claim 24, wherein step (d) further comprises the substep of modifying the map data as a function of the comparison data.

37. The method according to claim 24, wherein the octant navigator provides data to describe at least one of the rotation and the translation of the object on the surface of the k-space.

38. The method according to claim 24, wherein the octant navigator includes a plurality of gradients.

39. The method according to claim 38, further comprising the step of:

g) obtaining further navigator data which includes data for a further octant navigator, the further octant navigator including the gradients, wherein step (d) includes the substep of correcting the gradients of the further octant navigator based on a comparison of the data for the octant navigator and the map data.

40. The method according to claim 39, wherein steps (a) through (g) are performed for each slice of the k-space for the object, and wherein the gradients of the further octant navigator are corrected for each slice.

41. The method according to claim 40, further comprising the step of:

h) transforming the k-space volume obtained for a collection of the slices into an image.

42. The method according to claim 24, wherein the object is an anatomical structure, and further comprising the step of:

i) repeating steps (a) through (d) for a predetermined time period to complete a scan of the anatomical structure.

43. The method according to claim 42, wherein step (b) is performed as an initial step of the scan.

44. The method according to claim 24, wherein step (a) includes the substep of obtaining a scanning sequence which includes a signal portion, a spoiler portion and a navigator portion for the octant navigator, the navigator portion being provided between the signal portion and the spoiler portion.

45. A system of correcting for a motion of an object, comprising:

a processor configured to;

a) obtain navigator data for the object;

b) obtain map data for the object;

c) compare the navigator data with the map data to generate comparison data; and

d) correct at least one of a translation and a rotation of the object in real time as a function of the comparison data.

46. A software application provided for correcting a motion of an object, comprising:

a) a first module programmed to obtain navigator data for the object;

b) a second module programmed to map data for the object; and

c) a third module programmed to compare the navigator data with the map data to generate comparison data; and

fourth module programmed to direct at least one of a translation and a rotation of the object in real time as a function of the comparison data.

47. A system of correcting for a motion of an object, comprising the steps of:

a processor configured to;

a) obtain data of an octant navigator for the object;

b) obtain map data for the object;

c) compare the data of the octant navigator with the map data to generate comparison data; and

d) correct at least one of a translation and a rotation of the object as a function of the comparison data.

48. A software application provided for correcting a motion of an object, comprising:

a) a first module programmed to obtain data of an octant navigator for the object;

b) a second module programmed to map data for the object;

c) a third module programmed to compare the navigator data with the map data to generate comparison data; and

d) a fourth module programmed to direct at least one of a translation and a rotation of the object in real time as a function of the comparison data.

49. A scanning sequence provided for determining a position of an object, comprising:

a) a signal portion which includes at least one radio frequency signal;

b) an octant navigator portion which includes at least one octant navigator, the octant navigator being provided for allowing a measurement of at least one of a rotation and a translation of the object; and

c) a spoiler portion provided for reducing a signal magnitude of the scanning sequence,

wherein the navigator portion is provided between the signal portion and the spoiler portion.