Method of manufacturing local coils using pre-tuned non-magnetic circuitry modules

• US 20040231137A1
• Filed: 05/20/2003
• Published: 11/25/2004
• Est. Priority Date: 05/20/2003
• Status: Abandoned Application

• Current Assignee: Invivo Corporation (Koninklijke Philips N.V.)
• Original Assignee: Invivo Corporation (Koninklijke Philips N.V.)
• Inventors: Seeber, Derek
• Application Number:
  US10/441,709
• Publication Number:
  US 20040231137A1
• Time in Patent Office: Days
• US Class Current: 29/601
• 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 33/34076 Birdcage coils
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01R 12/52 connecting to other rigid printed circuits or like structures
• CPC Class Codes: Y10T 29/49016 Antenna or wave energy "plumbing" making
• CPC Class Codes: Y10T 29/49018 with other electrical component
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49169 Assembling electrical component directly to terminal or elongated conductor

Abstract

Manufacturing of local coils for magnetic resonance imaging systems operating to receive and transmit signals may be simply constructed by applying selected pre-manufactured, modular, multi-component circuits to antenna conductors of the coil.

Claims

1. A method of manufacturing local coils for use in magnetic resonance imaging systems comprising the steps of:

a) assembling a plurality of multi-component circuits, each on a substantially non-magnetic carrier having exposed terminals communicating with the multi-component circuits;

b) pre-characterizing the electrical parameters of the multi-component circuits to conform to defined electrical parameters;

c) assembling an antenna structure of the local coil using antenna conductors supported on at least one insulating support; and

d) attaching the terminals of at least one of the carriers containing one of the multi-component circuits to the conductors to the antenna structure of the local coil.

2. The method of manufacturing recited in claim 1 wherein the circuits are constructed of substantially non-magnetic components.

3. The method of manufacturing recited in claim 1 wherein the components include at least one non magnetic core inductor.

4. The method of manufacturing recited in claim 1 wherein the pre-characterization includes a step of tuning adjustable components in the multi-component circuits.

5. The method of manufacturing recited in claim 1 wherein the pre-characterization includes the step of testing the multi-component circuits for conformation with the defined electrical parameters.

6. The method of manufacturing recited in claim 1 wherein the electrical parameters are input impedance and output impedance at a given operating frequency.

7. The method of manufacturing recited in claim 1 wherein the multi-component circuits are selected from the group consisting of:

a phase shift network, a quadrature divider/combiner network, a bias T network, a radio frequency switch network; and

an isolation network and a matching network.

8. The method of manufacturing recited in claim 1 wherein the multi-component circuits are phase shift networks and step (a) includes the manufacture of a plurality of phase shift circuits of different standard values of phase shift and wherein step (d) includes the step of connecting at least two of the phase shift circuits in series to obtain a desired phase shift being a sum of standard values.

9. The method of manufacturing recited in claim 1 wherein the carrier is a printed circuit board having an insulating substrate and copper traces.

10. The method of manufacturing recited in claim 9 wherein the terminals are provided by plate-through holes connecting to pads at the bottom of the carrier.

11. The method of manufacturing recited in claim 1 including a non-magnetic housing for covering the multi-component circuit.

13. The pre-manufactured circuitry module recited in claim 11 wherein the non-magnetic components include at least one non-magnetic core inductor.

14. The pre-manufactured circuitry module recited in claim 11 wherein the housing is hermetically sealed about the multi-component circuit.

15. The pre-manufactured circuitry module recited in claim 11 wherein the multi-component circuit is a phase shift network having one of a set of predefined standard values.

16. The method of manufacturing recited in claim 14 wherein the standard values provide in combination of no greater than three modules, no less than 80 degrees of phase shift in one-degree increments.

12. A pre-manufactured circuitry module for a local coil for magnetic resonance imaging comprising:

a substantially non-magnetic circuit substrate receiving one or more substantially non-magnetic components to create a multi-component circuit selected from the group consisting of a phase shift network, a quadrature divider/combiner network, a bias T network, a radio frequency switch, an isolation network and a matching network, the multi-component circuit being pre-characterized to conform with defined electrical parameters;

a non-magnetic housing covering the multi-component circuit on the substrate; and

a set of non-magnetic terminals communicating between points on the multi-component circuit and areas exposed outside of the housing for attachment to conductors of the local coil.

17. The method of manufacturing recited in claim 12 wherein the multi-component circuit is frequency sensitive and tuned to a center frequency of a magnetic resonance machine.

18. The method of manufacturing recited in claim 17 wherein the frequency of the magnetic resonance machine is selected from the group consisting of 12.7, 43, 63.8 and 127 MHz.

19. A method of tuning a local MRI coil having an antenna portion and a signal lead connecting the antenna portion to an amplifier comprising the steps of:

a) selecting from a set of pre-manufactured and pre-tuned phase shifting modules having different denominations, a combination of phase shifting modules providing a given phase shift; and

b) connecting the selected phase shifting modules in series with each other and the signal lead to provide a total phase shift between the antenna portion and the amplifier of an odd multiple of ninety degrees.