Automated decoupling of RF receive coil elements

Patent metadata

Field	Value
Publication number	US-9869732-B2
Application number	US-201314653881-A
Country	US
Kind code	B2
Filing date	Sep 24, 2013
Priority date	Dec 20, 2012
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

The invention discloses a decoupling circuit ( 32 ) disposed between adjacent RF receive coil elements to automatically decouple the adjacent MRI RF receive coil elements. In one embodiment, the invention involves to inject an RF signal into a first coil element, to measure the RF signal coupled from the first coil element into a second coil element and to adjust the capacitance of the decoupling circuit such as to minimize the coupling between the first and the second coil elements.

First claim

The invention claimed is:

1. A magnetic resonance system, comprising:
a magnet which generates a static magnetic field in an examination region;
a RF transmitter and a RF transmit coil which generates RF pulses at a magnetic frequency to excite and manipulate resonance in the examination region;
at least one RF receive coil assembly including a plurality of RF receive coil elements configured to acquire magnetic resonance data from the examination region;
at least one RF receiver connected to the at least one RF receive coil assembly;
a scan controller configured to control the RF transmitter and RF receiver to perform scans;
a measurement and control unit configured to determine mutual inductance between adjacent first and second RF receive coil elements of the plurality of RF receive coil elements and determine a control signal based on the determined mutual inductance; and
a detuning circuit disposed between the adjacent first and second RF receive coil elements to automatically decouple the adjacent first and second RF receive coil elements in response to the control signal from the measurement and control unit;
a scan controller ( 20 ) configured to control the RF transmitter ( 24 ) and RF receiver ( 26 ),
wherein the detuning circuit comprises a capacitance bank including a number of capacitors and a number of switches for selectively switching in a desired number of the capacitors, each capacitor having a switch controlled by the control signal from the measurement and control unit,
wherein the measurement and control unit is further configured to control the detuning circuit by selecting the desired number of the capacitors that minimizes the determined mutual inductance between the adjacent first and second RF receive coil elements.

2. The magnetic resonance system according to claim 1 , further including:
a signal generator controlled by the measurement and control unit which induces an input signal into the first RF receive coil element of the adjacent first and second RF receive coil elements.

3. The magnetic resonance system according to claim 2 , wherein the measurement and control unit measures a output of the second RF receive coil element to determine if an induced signal was received by the second RF receive coil element in response to the input signal to the first RF receive coil element.

4. The magnetic resonance system according to claim 1 , wherein a output of the second RF receive coil element is compared to a predetermined threshold.

5. The magnetic resonance system according to claim 1 , wherein in response to a output of the second RF receive coil element being outside the predetermined threshold, the measurement and control unit adjusts the decoupling circuit to remove the mutual inductance between the adjacent first and second RF receive coil elements.

6. The magnetic resonance system according to claim 2 , wherein the input signal to the first RF receive coil element that induces the signal in the second RF receive coil element is provided by at least one of a RF injection probe, a high resistance network, and a high reactance network.

7. A system for automated decoupling of coil elements, the system comprising:
a first and second RF receive coil elements configured to acquire magnetic resonance data from a magnetic resonance system, wherein the first and second RF receive coil elements are adjacent to each other;
a measurement and control unit configured to determine mutual inductance between the first RF receive coil element and the second RF receive coil element output and to determine a control signal based on the determined mutual inductance; and
a detuning circuit disposed between the first and second RF receive coil elements to automatically decouple the first and second RF receive coil elements in response to the control signal from the measurement and control unit; and
wherein the detuning circuit comprises a capacitance bank including a number of capacitors and a number of switches for selectively switching in a desired number of the capacitors, each capacitor having a switch controlled by the control signal from the measurement and control unit,
wherein the measurement and control unit is further configured to control the detuning circuit by selecting the desired number of the capacitors that minimizes the determined mutual inductance between the adjacent first and second RF receive coil elements.

8. The system according to claim 7 , further including:
a signal generator controlled by the measurement and control unit configured to induce an input signal into the first RF receive coil element.

9. The system according to claim 8 , wherein the measurement and control unit measures the output of the second RF receive coil element to determine if an induced signal was received by the second RF receive coil element in response to the input signal to the first RF receive coil element.

10. The system according to claim 7 , wherein the output of the second RF receive coil element is compared to a predetermined threshold.

11. The system according to claim 7 , wherein in response to the output of the second coil element is outside the predetermined threshold, the measurement and control unit adjusts the decoupling circuit to remove the mutual inductance between the first and second coil elements.

12. The system according to claim 8 , wherein the input signal to the first RF receive coil element that induces the signal in the second RF receive coil element is provided by at least one of a RF injection probe, a high resistance network, and a high reactance network.

13. A method for automated decoupling of coil elements, the method comprising:
injecting a first signal into a first coil element;
measuring an induced signal coupled from the first coil element into a second coil element, wherein the second coil element is adjacent the first coil element;
determining by the measurement and control unit, mutual inductance between the first coil element and the second coil element;
adjusting a decoupling circuit to minimize the coupling between the first and second coil elements in response to the control signal from the measurement and control unit,
wherein the detuning circuit comprises a capacitance bank including a number of capacitors and a number of switches for selectively switching in a desired number of the capacitors, each capacitor having a switch controlled by the control signal from the measurement and control unit, and
wherein the adjusting step select the desired number of the capacitors that minimizes the determined mutual inductance between the adjacent first and second coil elements.

14. The method according to claim 13 , wherein the injecting act injects the first signal by at least one of a RF injection probe, a high resistance network, and a high reactance network.

15. A magnetic resonance system, including:
a magnet which generates a static magnetic field in an examination region;
a RF transmitter and a RF transmit coil which generates RF pulses at a magnetic frequency to excite and manipulate resonance in the examination region;
at least one RF receive coil assembly including a first and second coil element configured to acquire magnetic resonance data from the examination region;
at least one RF receiver connected to the at least one RF coil assembly;
a decoupling system which performs the method of claim 13 ; and
a scan controller configured to control the RF transmitter and RF receiver.

16. The magnetic resonance system according to claim 2 , further comprising:
an output amplifier which amplifies a signal received fro

Assignees

• Koninklijke Philips Nv

Inventors

• Reykowski Arne

Classifications

• G01R33/3614

  RF power amplifiers · CPC title

• G01R33/3415

  comprising arrays of sub-coils {, i.e. phased-array coils with flexible receiver channels} · CPC title

• G01R33/365 Primary

  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 title

• G01R33/34092

  RF coils specially adapted for NMR spectrometers · CPC title