Radio-frequency coil signal chain for a low-field MRI system

Patent metadata

Field	Value
Publication number	US-10890634-B2
Application number	US-201916418379-A
Country	US
Kind code	B2
Filing date	May 21, 2019
Priority date	May 21, 2018
Publication date	Jan 12, 2021
Grant date	Jan 12, 2021

Abstract

Methods and apparatus for reducing noise in RF signal chain circuitry for a low-field magnetic resonance imaging system are provided. A switching circuit in the RF signal chain circuitry may include at least one field effect transistor (FET) configured to operate as an RF switch at an operating frequency of less than 10 MHz. A decoupling circuit may include tuning circuitry coupled across inputs of an amplifier and active feedback circuitry coupled between an output of the amplifier and an input of the amplifier, wherein the active feedback circuitry includes a feedback capacitor configured to reduce a quality factor of an RF coil coupled to the amplifier.

First claim

What is claimed is:

1. A circuit configured to tune a radio frequency (RF) coil coupled to an amplifier of a low-field magnetic resonance imaging system, the circuit comprising:
tuning circuitry coupled across inputs of the amplifier; and
active feedback circuitry coupled between an output of the amplifier and an input of the amplifier, wherein the tuning circuitry comprises a tuning/matching network including at least one capacitor and at least one inductor.

2. The circuit of claim 1 , wherein the active feedback circuity is configured to provide a feedback signal 180 degrees out of phase with a center frequency of the RF coil.

3. The circuit of claim 1 , wherein the active feedback circuitry includes mutual inductive circuitry including at least one inductor.

4. The circuit of claim 3 , wherein the at least one inductor is configured to be coupled mutually to the RF coil.

5. The circuit of claim 1 , wherein the active feedback circuitry includes at least one feedback capacitor.

6. A circuit configured to tune a radio frequency (RF) coil coupled to an amplifier of a low-field magnetic resonance imaging system, the circuit comprising:
tuning circuitry coupled across inputs of the amplifier; and
active feedback circuitry coupled between an output of the amplifier and an input of the amplifier, wherein the active feedback circuity is configured to provide a first feedback signal 90 or 270 degrees out of phase with a center frequency of the RF coil.

7. The circuit of claim 6 , wherein a gain of the amplifier is tuned to be 90 or 270 degrees out of phase with the center frequency of the RF coil.

8. The circuit of claim 6 , wherein one or more components of the active feedback circuitry is configured to produce the first feedback signal being 90 or 270 degrees out of phase with the center frequency of the RF coil.

9. The circuit of claim 6 , wherein the active feedback circuitry is configured to provide a second feedback signal 180 degrees out of phase with the center frequency of the RF coil.

10. The circuit of claim 6 , wherein the tuning circuitry comprises a tuning capacitor coupled across the inputs of the amplifier.

11. A circuit configured to tune a radio frequency (RF) coil coupled to an amplifier of a low-field magnetic resonance imaging system, the circuit comprising:
active feedback circuitry coupled between an output of the amplifier and an input of the amplifier to reduce a quality factor of the RF coil, wherein the active feedback circuity is configured to provide a first feedback signal 90 or 270 degrees out of phase with a center frequency of the RF coil.

12. The circuit of claim 11 , wherein the active feedback circuitry includes at least one feedback capacitor.

13. The circuit of claim 11 , wherein a gain of the amplifier is tuned to be 90 or 270 degrees out of phase with the center frequency of the RF coil.

14. The circuit of claim 11 , wherein one or more components of the active feedback circuitry is configured to produce the first feedback signal being 90 or 270 degrees out of phase with the center frequency of the RF coil.

15. The circuit of claim 14 , wherein the active feedback circuitry is configured to provide a second feedback signal 180 degrees out of phase with the center frequency of the RF coil.

16. The circuit of claim 11 , wherein the active feedback circuity is configured to provide a second feedback signal 180 degrees out of phase with a center frequency of the RF coil.

Assignees

• Hyperfine Res Inc

Inventors

• Dyvorne Hadrien A
• Rearick Todd

Classifications

• G01R33/565

  Correction of image distortions, e.g. due to magnetic field inhomogeneities · 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

• G01R33/3854

  means for active and/or passive vibration damping or acoustical noise suppression in gradient magnet coil systems · CPC title

• G01R33/3657

  Decoupling of multiple RF coils wherein the multiple RF coils do not have the same function in MR, e.g. decoupling of a transmission coil from a receive coil · CPC title

• G01R33/3628

  Tuning/matching of the transmit/receive coil · CPC title