Method and apparatus for high-gain magnetic resonance imaging

• US 20070085544A1
• Filed: 10/17/2006
• Published: 04/19/2007
• Est. Priority Date: 10/18/2005
• Status: Active Grant

• Current Assignee: Tursiop Technologies LLC
• Original Assignee: Tursiop Technologies LLC
• Inventors: Viswanathan, Raju
• Granted Patent: US 7,714,577 B2
• Time in Patent Office: Days
• US Class Current: 324/318
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/34053 Solenoid coils; Toroidal coils
• CPC Class Codes: G01R 33/34061 Helmholtz coils
• CPC Class Codes: G01R 33/3415 comprising arrays of sub-coils , i.e. phased-array coils with flexible receiver channels
• CPC Class Codes: G01R 33/3808 Magnet assemblies for single-sided MR wherein the magnet assembly is located on one side of a subject only; Magnet assemblies for inside-out MR, e.g. for MR in a borehole or in a blood vessel, or magnet assemblies for fringe-field MR

Abstract

A method and apparatus for Magnetic Resonance Imaging with specialized imaging coils possessing high Signal-to-Noise-Ratio (SNR). Imaging and/or Radio Frequency receiving coils include a ballistic electrical conductor such as carbon nanotubes, the ballistic electrical conductor having a resistance that does not increase significantly with length. Due to their enhanced SNR properties, system designs with smaller static magnetic field strength can be constructed for the same quality of imaging, leading to substantial reductions in system size and cost, as well as to enhanced imaging with existing MRI systems.

Claims

1. A magnetic resonance imaging system having an enhanced signal-to-noise ratio, the system comprising:

a magnet system for providing a static magnetic field having a low magnetic field strength; and

at least one RF receiving coil assembly including;

a coiled electrical conducting element consisting essentially of carbon nanotube material; and

RF receiving circuitry having a large quality factor.

2. The system of claim 1, wherein the quality factor is substantially 100.

3. The system of claim 1, wherein the quality factor is greater than 15.

4. The system of claim 1, wherein the magnet system for providing a static magnetic field provides a magnetic field of strength of less than 1.5 Tesla.

5. The system of claim 1, wherein the magnet system for providing a static magnetic field provides a magnetic field of strength of between 0.1 to 1.5 Tesla.

6. The magnetic resonance imaging system of claim 1, wherein the magnet system for providing a static magnetic field provides a magnetic field of strength of between 0.02 Tesla and 3.00 Tesla.

7. The magnetic resonance imaging system of claim 1, wherein a plurality of RF receiving coils is included, each RF receiving coil including a coiled electrical conducting element consisting essentially of carbon nanotube material, and

wherein the plurality of RF receiving coils is configured as a phased array so as to enhance signal acquisition.

8. The magnetic resonance imaging system of claim 1, wherein the at least one RF receiving coil has between 3 and 500 complete windings of electrical conducting element consisting essentially of carbon nanotube material.

9. The magnetic resonance imaging system of claim 1, wherein the at least one RF receiving coil has at least 3 complete windings of electrical conducting element consisting essentially of carbon nanotube material.

10. The magnetic resonance imaging system of claim 9, wherein the windings of electrical conducting are of a winding diameter between 5 cm to 80 cm.

11. The magnetic resonance imaging system of claim 9, wherein the windings of electrical conducting are of a winding thickness between 20 nanometers and 500 microns.

12. The magnetic resonance imaging system of claim 1, wherein the at least one RF receiving coil assembly includes:

an opposed pair of coiled electrical conducting elements, each coiled electrical conducting element consisting essentially of carbon nanotube material in the form of a thin carbon nanotube film structured as a tightly wound ring of carbon nanotube film of a film thickness between 20 nanometers and 500 microns, and at least 3 turns of winding.

13. The magnetic resonance imaging system of claim 1, wherein the at least one RF receiving coil includes multiple layers of windings of electrical conducting element consisting essentially of carbon nanotube material.

14. The magnetic resonance imaging system of claim 1, wherein the magnet system is a permanent magnet.

15. The magnetic resonance imaging system of claim 1, wherein the at least one RF receiving coil can be moved by an operator.

16. The magnetic resonance imaging system of claim 1, wherein the at least one RF receiving coil includes a sensor to sense position and orientation of the at least one RF receiving coil.

17. The magnetic resonance imaging system of claim 1, wherein the RF receiving coil includes a coiled electrical conducting element having a plurality of winding turns in a spiral pattern.

18. The magnetic resonance imaging system of claim 1, wherein the RF receiving coil includes a coiled electrical conducting element having a plurality of winding turns in a conical helical pattern.

19. The magnetic resonance imaging system of claim 18, wherein the coiled electrical conducting element having a plurality of winding turns in a conical helical pattern is of an axial length L of as much as 9 cm.

20. The magnetic resonance imaging system of claim 18, wherein the coiled electrical conducting element having a plurality of winding turns in a conical helical pattern has a largest winding diameter in the range of 5 cm to 80 cm, and a smallest winding diameter being up to 20 times smaller than the largest winding diameter.

21. The magnetic resonance imaging system of claim 18, wherein the coiled electrical conducting element has a plurality of winding turns in a conical helical pattern, the plurality of winding turns having between 3 winding turns to 500 winding turns.

22. The magnetic resonance imaging system of claim 1, wherein the RF receiving coil includes a first coiled electrical conducting element having a plurality of winding turns in a conical helical pattern, followed by at least a second coiled electrical conducting element having a plurality of winding turns in a conical helical pattern.

23. The magnetic resonance imaging system of claim 1, wherein the RF receiving coil includes a coiled electrical conducting element having a plurality of winding turns in a tightly wound ring pattern.

24. The magnetic resonance imaging system of claim 1, wherein the at least one RF receiving coil includes a coiled electrical conducting element having a plurality of winding turns in a spiral pattern.

25. The magnetic resonance imaging system of claim 24, wherein the coiled electrical conducting element has between 3 and 500 complete windings of carbon nanotube material.

26. The magnetic resonance imaging system of claim 24, wherein the innermost windings of the coiled electrical conducting element are of a winding diameter of substantially 1 cm, and wherein the outermost windings of the coiled electrical conducting element are of a winding diameter of between 5 cm to 80 cm.

27. The magnetic resonance imaging system of claim 24, wherein the coiled electrical conducting element having a plurality of winding turns in a spiral pattern, the plurality including at least three complete turns of winding.

28. The magnetic resonance imaging system of claim 24, wherein the RF receiving coil further includes a second coiled electrical conducting element having a plurality of winding turns in a spiral pattern, the second coiled electrical conducting element being serially connected, with the same sense of winding, to a coiled electrical conducting element having a sensor to sense position and orientation.

29. The magnetic resonance imaging system of claim 28, wherein the coiled electrical conducting element of claim 28 and the second coiled electrical conducting element are separated by a distance between 2 mm and 15 mm.

30. The magnetic resonance imaging system of claim 28, further including between three and fifteen additional coiled electrical conducting elements in serial connection.

31. A magnetic resonance imaging system comprising:

a magnet system for providing a static inhomogeneous magnetic field within an imaging volume, such that the static inhomogeneous magnetic field is stronger in some portions of the imaging volume than in other portions of the imaging volume where the static magnetic field is weaker; and

at least one RF receiving coil including a coiled electrical conducting element consisting essentially of carbon nanotubes, the at least one RF receiving coil being of a configuration, and being positioned, such that;

a magnetic field of the RF receiving coil is stronger in some portions of the imaging volume than in other portions of the imaging volume where the magnetic field of the RF receiving coil is weaker; and

the magnetic field of the RF receiving coil is stronger in the portions of the imaging volume where the static inhomogeneous magnetic field is weaker.

32. For use in a magnetic resonance imaging system, an RF receiving coil assembly including:

a coiled electrical conducting element consisting essentially of carbon nanotube material; and

RF receiving circuitry having a large quality factor

33. A magnetic resonance imaging system having an enhanced signal-to-noise ratio, the system comprising:

a magnet system for providing a magnetic field; and

at least one RF receiving coil assembly including;

a coiled electrical conducting element consisting essentially of carbon nanotube material; and

RF receiving circuitry having a quality factor greater than 15.