Apparatus and method for real-time motion-compensated magnetic resonance imaging

• US 20090209846A1
• Filed: 06/26/2007
• Published: 08/20/2009
• Est. Priority Date: 06/28/2006
• Status: Abandoned Application

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Inventors: Bammer, Roland
• Application Number:
  US11/823,469
• Publication Number:
  US 20090209846A1
• Time in Patent Office: Days
• US Class Current: 600/421
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/064 using markers A61B5/062 takes precedence
• CPC Class Codes: A61B 5/1127 using markers
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: G01R 33/56308 Characterization of motion or flow; Dynamic imaging
• CPC Class Codes: G01R 33/56509 due to motion, displacement or flow, e.g. gradient moment nulling G01R33/567 takes precedence
• CPC Class Codes: G01R 33/5673 Gating or triggering based on a physiological signal other than an MR signal, e.g. ECG gating or motion monitoring using optical systems for monitoring the motion of a fiducial marker

Abstract

The present invention provides an apparatus and method for real-time motion compensated magnetic resonance imaging (MRI) of a human or animal. The apparatus includes one or more magnetic-resonance compatible cameras mounted on a coil of the MRI device, a calculation and storage device, and an interface operably connected to the MRI device and the calculation and storage device. The apparatus may also include a set of magnetic resonance compatible markers, where the markers are positioned on the human or animal. Alternatively, the apparatus may use a facial recognition algorithm to identify features of the human or animal. For the present invention, the frame of reference is defined by the animal or human being imaged, instead of the typical magnetic resonance coordinate system. Based on continuous positional information, the apparatus controls the magnetic resonance scanner so that it follows the human or animal'"'"'s motion.

Claims

1. An apparatus for real-time motion compensated magnetic resonance imaging of a human or animal, comprising:

a) one or more magnetic-resonance compatible cameras, wherein said cameras are mounted on a magnetic resonance coil of a magnetic resonance imaging device;

b) a calculation and storage device; and

c) an interface, wherein said interface is operably connected to said calculation and storage device and said magnetic resonance imaging device.

2. The apparatus as set forth in claim 1, further comprising a set of magnetic resonance compatible markers, wherein said markers are positioned on said human or animal.

3. The apparatus as set forth in claim 2, further comprising a magnetic-resonance compatible light source for illuminating said markers, wherein said light source is situated in proximity to said one or more magnetic-resonance compatible cameras.

4. The apparatus as set forth in claim 2, wherein said markers have varying diameters.

5. The apparatus as forth in claim 2, wherein said calculation and storage device comprises an algorithm for identifying said markers, an algorithm for determining the position of said markers in three dimensions, and an algorithm for determining the rotation and translation of said markers.

6. The apparatus as set forth in claim 1, further comprising a housing for each of said one or more magnetic-resonance compatible cameras.

7. The apparatus as set forth in claim 6, wherein said housing is covered by grounded copper shielding, and wherein a lens of each of said one or more cameras is uncovered by said grounded copper shielding or covered by a visibly transparent but RF-shielded copper mesh.

8. The apparatus as set forth in claim 6, wherein said housing further comprises thermocouples, wherein said thermocouples are mounted to said housing.

9. The apparatus as set forth in claim 1, further comprising a control and transfer system, wherein said control and transfer system transfers data from said cameras to said calculation and storage device.

10. The apparatus as set forth in claim 9, further comprising a processor, wherein said processor provides a line conditioning and voltage protection circuit for said control and transfer system.

11. The apparatus as set forth in claim 1, wherein said interface is a software process or a hardware interface.

12. The apparatus as set forth in claim 1, wherein said calculation and storage device comprises a facial recognition algorithm for identifying features of said human or said animal, an algorithm for determining the position of said features in three dimensions, and an algorithm for determining the rotation and translation of said features.

13. A method of motion compensating magnetic resonance imaging of a human or animal in real time, comprising the steps of:

a) mounting one or more magnetic-resonance compatible cameras on a magnetic resonance coil of a magnetic resonance imaging device;

b) positioning a set of magnetic-resonance compatible markers on said human or animal;

c) acquiring an image of said markers with said cameras;

d) identifying said markers;

e) determining the position of said markers in three dimensions;

f) determining the rotation and translation of said markers; and

g) modifying geometrical prescriptions of said magnetic resonance imaging device based on said determining of said rotation and said translation.

14. The method as set forth in claim 13, further comprising imaging said markers using magnetic resonance imaging;

15. The method as set forth in claim 14, further comprising transforming the positions of said markers from a coordinate system of one or more of said cameras to a coordinate system of said magnetic resonance imaging device.

16. The method as set forth in claim 13, wherein said positioning comprises attaching spheres of equal or varying but known sizes and spacings to a central sphere, and attaching said central sphere to said human or animal.

17. The method as set forth in claim 13, further comprising utilizing a parallel imaging reconstruction algorithm.

18. A method of motion compensating magnetic resonance imaging of a human or animal in real time, comprising the steps of:

a) mounting at least two magnetic-resonance compatible cameras on a magnetic resonance coil of a magnetic imaging device;

b) acquiring an image of the head of said human or animal with said cameras;

c) identifying features of said head using a facial recognition algorithm;

d) determining the position of said features in three dimensions;

e) determining the rotation and translation of said features; and

f) modifying geometrical prescriptions of said magnetic imaging device based on said determining of said rotation and said translation.

19. The method as set forth in claim 18, wherein said identifying comprises use of at least one of Haar classifiers or a CAMSHIFT algorithm.

20. The method as set forth in claim 18, further comprising utilizing a parallel imaging reconstruction algorithm.