Apparatus for dynamic angular position tracking

• US 20030178995A1
• Filed: 03/25/2002
• Published: 09/25/2003
• Est. Priority Date: 03/25/2002
• Status: Active Grant

• Current Assignee: New York State Department of Mental Hygiene Office
• Original Assignee: New York State Department of Mental Hygiene Office
• Inventors: Helpern, Joseph A., Peshkovsky, Alexey
• Granted Patent: US 6,980,847 B2
• Time in Patent Office: Days
• 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 magnetic resonance imaging (“MRI”) system and method of correcting for the motion of a subject during an MRI scan. The motion of a subject in an MRI scan is corrected by acquiring nuclear magnetic resonance (“NMR”) spectra of an ordered material attached to a subject, wherein there is a dependence on the NMR spectra of the ordered material'"'"'s orientation in a magnetic field, and determining an orientation of the subject. Correction information is then supplied to a primary spectrometer channel which is used to execute an MRI scan, and an imaging pulse sequence of the MRI scan is adjusted to correct the subject'"'"'s orientation.

Claims

1. A method of correcting for the motion of a subject during a magnetic resonance imaging (“

MRI”

) scan, comprising;

acquiring a nuclear magnetic resonance (“

NMR”

) spectra of an ordered material attached to a subject, wherein there is a dependence on the NMR spectra of the ordered material'"'"'s orientation in a magnetic field; and

determining an orientation of the subject.

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

supplying correction information to a primary spectrometer channel, which is used to execute an MRI scan, based on the determined orientation of the subject to adjust at least one MRI scan parameter.

3. The method according to claim 2, further comprising:

adjusting an imaging pulse sequence of the MRI scan, based on the correction information, to correct the subject'"'"'s orientation.

4. The method according to claim 3, wherein the imaging pulse sequence of the MRI scan is adjusted based on a request.

5. The method according to claim 1, wherein the ordered material is a single crystal, oriented polymer, liquid crystal, or the like.

6. The method according to claim 1, further comprising:

attaching a radio frequency (“

RF”

) transmit/receive circuit to the subject.

7. The method according to claim 6, wherein the ordered material is embedded in a solenoid coil in the RF transmit/receive circuit.

8. The method according to claim 1, wherein the spectra of the ordered material are acquired with an independent spectrometer channel of the MRI system that operates at a separate frequency from the primary spectrometer channel executing the MRI scan.

9. The method according to claim 1, wherein the orientation of the subject is determined by correlating changes in the peak splittings of the NMR spectra of the ordered material with the changes in the subject'"'"'s orientation.

10. The method according to claim 9, wherein the subject'"'"'s orientation is determined by accessing calibration tables pertaining to the ordered material.

11. The method according to claim 1, wherein the orientation of the subject is determined by correlating changes in the peak shiftings of the NMR spectra of the ordered material with the changes in the subject'"'"'s orientation.

12. The method according to claim 11, wherein the subject'"'"'s orientation is determined by accessing calibration tables pertaining to the ordered material.

13. The method according to claim 1, further comprising:

recording an image after the imaging pulse sequence is adjusted.

14. The method according to claim 1, wherein two ordered materials are employed.

15. The method according to claim 14, wherein two ordered materials with different resonance amplitudes are employed.

16. The method according to claim 14, wherein at least one ordered material is oriented to detect changes in pitch.

17. The method according to claim 14, wherein at least one ordered material is oriented to detect changes in yaw.

18. A method of determining the initial orientation of an ordered material during an MRI scan, comprising:

varying an ordered material'"'"'s orientation in an MRI scanner'"'"'s magnetic field, such that its splitting maxima or shifting maxima are located, in order to find the ordered material'"'"'s principal axes;

sealing the ordered material in its initial orientation in a solenoid coil included in an RF transmit/receive circuit; and

acquiring an NMR spectra of the ordered material at a range of angles.

19. The method according to claim 18, further comprising:

organizing the acquired spectra into calibration tables.

20. The method according to claim 18, wherein there is a dependence on the NMR spectra of the ordered material'"'"'s orientation in a magnetic field.

21. The method according to claim 18, wherein the ordered material is a single crystal, oriented polymer, liquid crystal, or the like.

22. The method according to claim 18, wherein the ordered material is sealed using an adhesive, such as an epoxy, glue, or the like.

23. The method according to claim 18, wherein the NMR spectra acquired is of the ordered material rotated about the horizontal X-axis by a range of pitch angles.

24. The method according to claim 18, wherein the NMR spectra acquired is of the ordered material rotated about the vertical Y-axis by a range of yaw angles.

25. A method of correcting for the motion of a subject during an MRI scan, comprising:

attaching an RF transmit/receive circuit to a subject, wherein the RF transmit/receive circuit includes a pre-calibrated ordered material embedded in a solenoid coil;

acquiring an NMR spectra of the ordered material, wherein there is a dependence on the NMR spectra of the ordered material'"'"'s orientation in a magnetic field;

determining an orientation of the subject by accessing calibration tables pertaining to the ordered material;

supplying correction information to a primary spectrometer channel, which is used to execute an MRI scan, based on the determined orientation of the subject to adjust at least one MRI scan parameter; and

adjusting an imaging pulse sequence of the MRI scan, based on the correction information, to correct the subject'"'"'s orientation.

26. A system of correcting for the motion of a subject during an MRI scan, comprising:

means for acquiring an NMR spectra of an ordered material attached to a subject, wherein there is a dependence on the NMR spectra of the ordered material'"'"'s orientation in the magnetic field; and

means for determining the orientation of the subject.

27. The system according to claim 26, further comprising:

means for supplying correction information to a primary spectrometer channel, which is used to execute an MRI scan, based on the determined orientation of the subject to adjust at least one MRI scan parameter.

28. The system according to claim 27, further comprising:

means for adjusting an imaging pulse sequence of the MRI scan, based on the correction information, to correct the subject'"'"'s orientation.

29. The system according to claim 28, wherein the imaging pulse sequence of the MRI scan is adjusted based on a request.

30. The system according to claim 26, wherein the ordered material is a single crystal, oriented polymer, liquid crystal, or the like.

31. The system according to claim 26, further comprising:

means for attaching a radio frequency RF transmit/receive circuit to the subject.

32. The system according to claim 31, wherein the ordered material is embedded in a solenoid coil in the RF transmit/receive circuit.

33. The system according to claim 26, wherein the spectra of the ordered material are acquired with an independent spectrometer channel of the MRI system that operates at a separate frequency from the primary spectrometer channel executing the MRI scan.

34. The method according to claim 26, wherein the orientation of the subject is determined by correlating changes in the peak splittings or peak shiftings of the NMR spectra of the ordered material with the changes in the subject'"'"'s orientation.

35. The system according to claim 34, wherein the subject'"'"'s orientation is determined by accessing calibration tables pertaining to the ordered material.

36. The system according to claim 26, further comprising:

means for recording an image after the imaging pulse sequence is adjusted.

37. The system according to claim 26, wherein two ordered materials are employed.

38. The system according to claim 37, wherein two ordered materials with different resonance amplitudes are employed.

39. The system according to claim 37, wherein at least one ordered material is oriented to detect changes in pitch.

40. The system according to claim 37, wherein at least one ordered material is oriented to detect changes in yaw.

41. A system of determining the initial orientation of an ordered material during an MRI scan, comprising:

means for varying an ordered material'"'"'s orientation in an MRI scanner'"'"'s magnetic field, such that its splitting maxima or shifting maxima are located, in order to find the ordered material'"'"'s principal axes;

means for sealing the ordered material in its initial orientation in a solenoid coil included in an RF transmit/receive circuit; and

means for acquiring an NMR spectra of the ordered material at a range of angles.

42. The system according to claim 41, further comprising:

means for organizing the acquired spectra into calibration tables

43. The system according to claim 41, wherein there is a dependence on the NMR spectra of the ordered material'"'"'s orientation in a magnetic field.

44. The system according to claim 41, wherein the ordered material is a single crystal, oriented polymer, liquid crystal, or the like.

45. The system according to claim 41, wherein the ordered material is sealed using an adhesive, such as an epoxy, glue, or the like.

46. The system according to claim 41, wherein the NMR spectra acquired is of the ordered material rotated about the horizontal X-axis by a range of pitch angles.

47. The system according to claim 41, wherein the NMR spectra acquired is of the ordered material rotated about the vertical Y-axis by a range of yaw angles.

48. An apparatus for correcting for the motion of a subject during an MRI scan, comprising:

an MRI system; and

a computer programmed to;

acquire an NMR spectra of an ordered material attached to a subject, wherein there is a dependence on the NMR spectra of the ordered material'"'"'s orientation in a magnetic field; and

determine an orientation of the subject.

49. The apparatus of claim 48, wherein the computer is further programmed to supply correction information to a primary spectrometer channel, which is used to execute an MRI scan, based on the determined orientation of the subject to adjust at least one MRI scan parameter.

50. The apparatus of claim 48, wherein the computer is further programmed to adjust an imaging pulse sequence of the MRI scan based on the correction information, to correct the subject'"'"'s orientation.

51. The apparatus of claim 48, wherein the computer is further programmed to adjust the imaging pulse sequence of the MRI scan based on a user'"'"'s request.

52. The apparatus of claim 48, wherein the computer is further programmed to acquire the spectra of the ordered material with an independent spectrometer channel of the MRI system that operates independently from the primary spectrometer channel executing the MRI scan.

53. The apparatus of claim 48, wherein the computer is further programmed to determine the orientation of the subject by correlating changes in the peak splittings or peak shiftings of the NMR spectra of the ordered material with changes in the subject'"'"'s orientation.

54. The apparatus of claim 53, wherein the computer is further programmed to determine the orientation of the subject by accessing pre-determined calibration tables pertaining to the ordered material.

55. The apparatus of claim 48, wherein the computer is further programmed to record an image after the imaging pulse sequence is adjusted.

56. A program stored on a computer readable medium and executable by a processor comprising:

instruction code which, when executed by the processor, acquires an NMR spectra of an ordered material attached to a subject, wherein there is a dependence on the NMR spectra of the ordered material'"'"'s orientation in a magnetic field;

instruction code which, when executed by the processor, determines an orientation of the subject;

instruction code which, when executed by the processor, supplies correction information to a primary spectrometer channel, which is used to execute an MRI scan, based on the determined orientation of the subject to adjust at least one MRI scan parameter; and

instruction code which, when executed by the processor, adjusts an imaging pulse sequence of an MRI scan, based on the correction information, to correct the subject'"'"'s orientation.