Ferromagnetic augmentation for magnetic resonance imaging

Patent metadata

Field	Value
Publication number	US-9638773-B2
Application number	US-201514846255-A
Country	US
Kind code	B2
Filing date	Sep 4, 2015
Priority date	Sep 5, 2014
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

In some aspects, a magnetic system for use in a low-field MRI system. The magnetic system comprises at least one electromagnet configured to, when operated, generate a magnetic field to contribute to a B 0 field for the low-field MRI system, and at least one permanent magnet to produce a magnetic field to contribute to the B 0 field.

First claim

What is claimed is:

1. A magnetic system for use in a magnetic resonance imaging system, the magnetic system comprising:
at least one electromagnet configured to, when operated, generate a magnetic field to contribute to a B 0 field for the magnetic resonance imaging system, the electromagnet comprising at least one electromagnetic coil wound using a copper or aluminum conductor to generate a magnetic field; and
at least one ferromagnetic component configured to capture and direct at least some of the magnetic field generated by the electromagnet to increase the magnetic flux density within an imaging region of the magnetic resonance imaging system,
wherein the B 0 field generated is less than or equal to approximately 0.2T and greater than or equal to approximately 0.1T.

2. A magnetic system for use in a magnetic resonance imaging system, the magnetic system comprising:
at least one electromagnet configured to, when operated, generate a magnetic field to contribute to a B 0 field for the magnetic resonance imaging system, the electromagnet comprising at least one electromagnetic coil wound using a copper or aluminum conductor to generate a magnetic field; and
at least one ferromagnetic component configured to capture and direct at least some of the magnetic field generated by the electromagnet to increase the magnetic flux density within an imaging region of the magnetic resonance imaging system,
wherein the B 0 field generated is less than or equal to approximately 0.1T and greater than or equal to approximately 50 mT.

3. A The magnetic system of claim 2 for use in a magnetic resonance imaging system, the magnetic system comprising:
at least one electromagnet configured to, when operated, generate a magnetic field to contribute to a B 0 field for the magnetic resonance imaging system, the electromagnet comprising at least one electromagnetic coil wound using a copper or aluminum conductor to generate a magnetic field; and
at least one ferromagnetic component configured to capture and direct at least some of the magnetic field generated by the electromagnet to increase the magnetic flux density within an imaging region of the magnetic resonance imaging system,
wherein the B 0 field generated is less than or equal to approximately 50 mT and greater than or equal to approximately 20 mT.

4. A magnetic system for use in a magnetic resonance imaging system, the magnetic system comprising:
at least one electromagnet configured to, when operated, generate a magnetic field to contribute to a B 0 field for the magnetic resonance imaging system, the electromagnet comprising at least one electromagnetic coil wound using a copper or aluminum conductor to generate a magnetic field; and
at least one ferromagnetic component configured to capture and direct at least some of the magnetic field generated by the electromagnet to increase the magnetic flux density within an imaging region of the magnetic resonance imaging system,
wherein the B 0 field generated is less than or equal to approximately 20 mT and greater than or equal to approximately 10 mT.

5. A magnetic system for use in a magnetic resonance imaging system, the magnetic system comprising:
at least one electromagnet configured to, when operated, generate a magnetic field to contribute to a B 0 field for the magnetic resonance imaging system, the electromagnet comprising at least one electromagnetic coil wound using a copper or aluminum conductor to generate a magnetic field, wherein the at least one electromagnet comprises a pair of B 0 coils including a first B 0 coil and a second B 0 coil arranged in a bi-planar configuration;
at least one ferromagnetic component configured to capture and direct at least some of the magnetic field generated by the electromagnet to increase the magnetic flux density within an imaging region of the magnetic resonance imaging system, wherein the at least one ferromagnetic component is configured to increase the field strength and/or alter the homogeneity of the B 0 field in the imaging region between the first B 0 coil and the second B 0 coil; and
at least one laminate panel having at least one electromagnetic component fabricated thereon, wherein the at least one laminate panel comprises at least one x-gradient coil, at least one y-gradient coil, and at least one z-gradient coil to provide spatial encoding in x, y, and z directions, respectively.

6. The magnetic system of claim 5 , wherein the at least one ferromagnetic component comprises a ferromagnetic structure connected to the first B 0 coil and the second B 0 coil to form a magnetic circuit that provides at least one return path for magnetic flux generated by the first B 0 coil and the second B 0 coil through the ferromagnetic structure.

7. The magnetic system of claim 6 , wherein the ferromagnetic structure provides the at least one return path for magnetic flux along at least one side of the ferromagnetic structure.

8. The magnetic system of claim 7 , wherein the ferromagnetic structure provides a plurality of return paths for magnetic flux along sides of the ferromagnetic structure.

9. The magnetic system of claim 7 , wherein the ferromagnetic structure comprises a C-shaped ferromagnetic structure that provides a return path for magnetic flux along only one side of the ferromagnetic structure.

10. The magnetic system of claim 6 , wherein the ferromagnetic structure comprises at least one beveled corner to reduce a magnetic reluctance around the at least one beveled corner.

11. The magnetic system of claim 6 , wherein the ferromagnetic structure comprises a plurality of ferromagnetic posts configured to provide the at least one return path for magnetic flux.

12. The magnetic system of claim 11 , wherein at least one of the plurality of ferromagnetic posts is removable from the low-field MRI system.

13. The magnetic system of claim 6 , wherein the at least one ferromagnetic component further comprises at least one first ferromagnetic component located adjacent to the first B 0 coil and/or the second B 0 coil to alter where the magnetic flux exits the ferromagnetic structure.

14. The magnetic system of claim 13 , wherein the ferromagnetic structure comprises a first ferromagnetic material and wherein the at least one first ferromagnetic component located adjacent to the first B 0 coil and/or the second B 0 coil comprises a second ferromagnetic material different than the first ferromagnetic material.

15. The magnetic system of claim 5 , wherein the at least one ferromagnetic component comprises one or more solid ferromagnetic components.

16. The magnetic system of claim 5 , wherein the at least one laminate panel comprises at least one B 0 coil and/or at least one shim coil.

17. The magnetic system of claim 5 , wherein the at least one ferromagnetic component comprises at least one shim ring located adjacent to the first B 0 coil and/or the second B 0 coil.

18. The magnetic system of claim 5 , wherein the at least one ferromagnetic component comprises a plurality of ferromagnetic shim pieces located adjacent to the first B 0 coil and/or the second B 0 coil.

19. The magnetic system of claim 5 , wherein the at least one ferromagnetic component comprises at least one ferromagnetic pole piece located adjacent to the first B 0 coil and/or the second B 0 coil.

20. The magnetic system of claim 19 , wherein the at least one ferromagnetic pole piece comprises a pole piece having a non-rectangular shape.

21. The magnetic system of claim

Assignees

• Hyperfine Res Inc

Inventors

• Poole Michael Stephen
• Rearick Todd
• Rothberg Jonathan M

Classifications

• H01F7/06

  Electromagnets; Actuators including electromagnets {(electric coils H01F5/00; devices for holding workpieces using electric force B23Q3/15; load-engaging elements for lifting articles electromagnetically B66C1/06; electromagnetic couplings F16D27/00; magnetic brakes F16D63/002; electromagnetically operated valves F16K11/24, F16K31/00; analysing materials by magnetic means G01N27/72, G01N27/80; electromagnets for winding mechanical clocks G04C1/02; electromagnetic relays H01H51/00; windings for salient poles of dynamo-electric machines H02K3/18; electromagnets for telegraphic communication H04L; for arc lamps H05B31/28)} · CPC title

• G01R33/383

  using permanent magnets · CPC title

• G01R33/28

  Details of apparatus provided for in groups G01R33/44 - G01R33/64 · CPC title

• G01R33/5608 Primary

  Data processing and visualization specially adapted for MR, e.g. for feature analysis and pattern recognition on the basis of measured MR data, segmentation of measured MR data, edge contour detection on the basis of measured MR data, for enhancing measured MR data in terms of signal-to-noise ratio by means of noise filtering or apodization, for enhancing measured MR data in terms of resolution by means for deblurring, windowing, zero filling, or generation of gray-scaled images, colour-coded images or images displaying vectors instead of pixels (image data processing or generation, in general G06T) · CPC title

• G01R33/445 Primary

  MR involving a non-standard magnetic field B0, e.g. of low magnitude as in the earth's magnetic field or in nanoTesla spectroscopy, comprising a polarizing magnetic field for pre-polarisation, B0 with a temporal variation of its magnitude or direction such as field cycling of B0 or rotation of the direction of B0, or spatially inhomogeneous B0 like in fringe-field MR or in stray-field imaging · CPC title