Transformer assembly for a magnetic resonance imaging system

• US 8,674,799 B2
• Filed: 06/10/2010
• Issued: 03/18/2014
• Est. Priority Date: 06/10/2010
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Taracila, Victor, Robb, Fraser, Zemskov, Aleksey, Alagappan, Vijayanand, Navarro, Miguel
• Primary Examiner(s): Chan, Tsz
• Application Number:
  US12/797,810
• Publication Number:
  US 20110304422A1
• Time in Patent Office: 1,377 Days
• Field of Search: 336/200, 336/232
• US Class Current: 336/200
• CPC Class Codes: G01R 33/34007 Manufacture of RF coils, e.g. using printed circuit board technology; additional hardware for providing mechanical support to the RF coil assembly or to part thereof, e.g. a support for moving the coil assembly relative to the remainder of the MR system
• CPC Class Codes: G01R 33/3415 comprising arrays of sub-coils , i.e. phased-array coils with flexible receiver channels
• CPC Class Codes: G01R 33/3628 Tuning/matching of the transmit/receive coil
• CPC Class Codes: G01R 33/365 Decoupling of multiple RF coils wherein the multiple RF coils have the same function in MR, e.g. decoupling of a receive coil from another receive coil in a receive coil array, decoupling of a transmission coil from another transmission coil in a transmission coil array
• CPC Class Codes: H01F 19/04 Transformers or mutual inductances suitable for handling frequencies considerably beyond the audio range resonant circuits H03H
• CPC Class Codes: H01F 21/12 discontinuously variable, e.g. tapped
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

A transformer assembly includes a substrate having a first surface and an opposing second surface, a first spiral wound inductive coil formed on the first surface, and a second spiral wound inductive coil formed on the first surface; the first and second spiral wound inductive coils forming a double spiral arrangement on the first surface such that the first coil is inductively coupled to the second coil. An RF coil including the transformer assembly and a method of fabricating the transformer assembly are also described.

Claims

1. A transformer assembly for a magnetic resonance imaging (MRI) system, said transformer assembly comprising:

a substrate having a first surface and an opposing second surface;

a first and a second spiral wound inductive coils formed on the first surface and forming a first double spiral arrangement such that the first coil is inductively coupled to the second coil;

a third and a fourth-spiral wound inductive coils formed on the second surface and forming a second double spiral arrangement such that the third coil is inductively coupled to the fourth coil;

a plurality of openings extending through the first, the second, the third, and the fourth coils; and

a pair of pins being inserted into select ones of the plurality of openings through the first, the second, the third, and the fourth coils to adjust a mutual inductance of the transformer assembly in the MRI system.

2. A transformer assembly in accordance with claim 1 wherein the first spiral wound inductive coil is symmetrical with the third spiral wound inductive coil and the second spiral wound inductive coil is symmetrical with the fourth spiral wound inductive coil.

3. A transformer assembly in accordance with claim 1 wherein the first and third-coils are configured to be electrically coupled to a first capacitor and the second and fourth coils are configured to be electrically coupled to a second capacitor.

4. A transformer assembly in accordance with claim 1 wherein the first and third coils are configured to be electrically coupled in series to a respective capacitor, the pins being inserted into the openings based on the capacitance of the first and second capacitors.

5. A transformer assembly in accordance with claim 1 wherein the first coil is interleaved with the second coil and the third coil is interleaved with the fourth coil.

6. A transformer assembly in accordance with claim 1 wherein the first coil, the second coil, the third coil, and the fourth coil each form an Archimedes spiral.

7. A transformer assembly in accordance with claim 1 wherein the substrate is fabricated from a dielectric material and the first and second coils are fabricated from a copper material.

8. A transformer assembly in accordance with claim 1 wherein the first and second coils include a plurality of turns that are coplanar.

9. A multiple channel array coil for a magnetic resonance imaging (MRI) system, comprising:

a first radio frequency (RF) coil;

a second RF coil; and

a transformer coupled between the first and second coils, the transformer comprising;

a substrate having a first surface and an opposing second surface;

a first and a second spiral wound inductive coils formed on the first surface and forming a double spiral arrangement such that the first coil is inductively coupled to the second coil;

a third and a fourth spiral wound inductive coils formed on the second surface and forming a double spiral arrangement such that the third coil is inductively coupled to the fourth coil;

a plurality of openings extending through the first, the second, the third, and the fourth coils; and

a pair of pins being inserted into selected ones of the plurality of openings through the first, the second, the third, and the fourth coils to adjust a mutual inductance of the transformer assembly in the MRI system.

10. An array coil in accordance with claim 9 wherein the first and third spiral wound inductive coils are configured to be electrically coupled to a first capacitor and the second and fourth spiral wound inductive coils are electrically coupled to a second capacitor.

11. An array coil in accordance with claim 9 wherein the first and third-coils are electrically coupled in series to a first capacitor and the second and fourth coils are electrically coupled to a second capacitor, the pins being inserted into the openings based on the capacitance of the first and second capacitors.

12. An array coil in accordance with claim 9 wherein the first coil is interleaved with the second coil and the third coil is interleaved with the fourth coil.

13. An array coil in accordance with claim 9 wherein the first coil, the second coil, the third coil, and the fourth coil each form an Archimedes spiral.

14. An array coil in accordance with claim 9 the substrate is fabricated from a dielectric material and the first and second coils are fabricated from a copper material.

15. A transformer assembly in accordance with claim 9 wherein the first and second coils include a plurality of turns that are coplanar.

16. An array coil in accordance with claim 9 wherein the first RF coil and the second RF coil comprise surface coils.

17. A method of fabricating a transformer assembly for a magnetic resonance imaging (MRI), said method comprising:

forming a first spiral inductor and a second spiral inductor on a first surface of a dielectric such that the first spiral inductor is interleaved with the second spiral inductor;

forming a third-spiral inductor and a fourth spiral inductor on the second surface of the substrate such that the third spiral inductor is interleaved with the fourth spiral inductor;

forming a plurality of openings through the first, the second, the third, and the fourth coils; and

inserting a pair of pins into selected ones of the plurality of openings through the first, the second, the third, and the fourth coils to adjust a mutual inductance of the transformer assembly in the MRI system.

18. The method of claim 17, wherein the first and third coils are electrically coupled in series to a first capacitor and the second and fourth coils are electrically coupled to a second capacitor, said method further comprising inserting the pins into the openings based on the capacitance of the first and second capacitors.

19. The method of claim 17, wherein the first coil is interleaved with the second coil and the third coil is interleaved with the fourth coil.