Body coil having a pre-amplification unit configured to provide a detuning effect

Patent metadata

Field	Value
Publication number	US-10557900-B2
Application number	US-201615200522-A
Country	US
Kind code	B2
Filing date	Jul 1, 2016
Priority date	Jul 16, 2015
Publication date	Feb 11, 2020
Grant date	Feb 11, 2020

Abstract

The embodiments relate to a body coil, to a magnetic resonance device, and to a method for operating a magnetic resonance device. The body coil includes at least one antenna unit and at least one pre-amplification unit, wherein the pre-amplification unit is arranged at a feed point of the antenna unit, wherein the pre-amplification unit has an input reflection factor at the feed point of the antenna unit whose value is greater than 0.7.

First claim

The invention claimed is:

1. A body coil comprising:
at least one antenna unit free from detune circuits; and
at least one pre-amplification unit comprising a pre-amplifier and a cable or the pre-amplifier, the cable, and at least one transformation element,
wherein the pre-amplification unit is arranged at a feed point of the antenna unit,
wherein the pre-amplification unit is configured to amplify magnetic resonance signals received by the body coil, and
wherein, at the feed point of the antenna unit, the pre-amplifier has an input reflection factor transformed by a length of the cable, the at least one transformation element, or a combination thereof such that the value of the input reflection factor is greater than 0.7 and is configured to provide a detuning effect.

2. The body coil of claim 1 , wherein the body coil comprises a birdcage coil, a TEM-antenna, a saddle coil, or a combination thereof.

3. The body coil of claim 1 , wherein the body coil comprises a birdcage coil having at least one end ring and at least one rod, and
wherein the feed point is located at the at least one end ring, centrally on the at least one rod, or both at the at least one end ring and centrally on the at least one rod.

4. The body coil of claim 1 wherein the pre-amplification unit comprises a switch for connecting the pre-amplifier to the feed point of the antenna unit.

5. The body coil of claim 1 , wherein the pre-amplification unit comprises high-power impedance.

6. The body coil of claim 5 , wherein the high-power impedance has the input reflection factor whose value is greater than 0.7.

7. The body coil of claim 5 , wherein the pre-amplification unit comprises a switch for connecting the high-power impedance to the feed point of the antenna unit.

8. The body coil of claim 1 , wherein the input reflection factor of the pre-amplification unit has a phase in a range of 165° to 195° at the feed point of the antenna unit.

9. The body coil of claim 8 , wherein the transformation element of the pre-amplification unit is configured to adjust the phase of the input reflection factor.

10. The body coil of claim 8 , wherein the cable length of the pre-amplification unit is matched to the phase for adjusting the phase of the input reflection factor.

11. The body coil of claim 1 , wherein the pre-amplification unit comprises a first switch configured to switch the feed point of the antenna unit between a transmitting path and a receiving path,
wherein the pre-amplification unit in the receiving path comprises terminating impedance, the pre-amplifier, and a second switch,
wherein the second switch is configured to switch between the terminating impedance and the pre-amplifier.

12. The body coil of claim 11 , wherein the terminating impedance has an input reflection factor of −1.

13. The body coil of claim 11 , wherein the body coil is configured to excite
excitation signals of an excitation signal wavelength, and
wherein the length of cable is between the feed point of the antenna unit and the terminating impedance, which is an integral multiple of half the wavelength of the excitation signal wavelength.

14. The body coil of claim 11 , wherein the first switch has a higher power than the second switch.

15. The body coil of claim 1 , wherein the at least one transformation element comprises a phase shifter.

16. A magnetic resonance device comprising:
at least one local coil; and
a body coil comprising:
at least one antenna unit free from detune circuits; and
at least one pre-amplification unit comprising a pre-amplifier and a cable or the pre-amplifier, the cable, and at least one transformation element,
wherein the pre-amplification unit is arranged at a feed point of the antenna unit,
wherein the pre-amplification unit is configured to amplify magnetic resonance signals received by the body coil, and
wherein, at the feed point of the antenna unit, the pre-amplifier has an input reflection factor transformed by a length of the cable, the at least one transformation element, or a combination thereof such that the value of the input reflection factor is greater than 0.7 and is configured to provide a detuning effect.

17. A method for operating a magnetic resonance device having a body coil and at least one local coil, wherein the body coil comprises at least one antenna unit free from detune circuits and at least one pre-amplification unit having a pre-amplifier and a cable or the pre-amplifier, the cable, and at least one transformation element, wherein the pre-amplification unit is arranged at a feed point of the antenna unit, and wherein, at the feed point of the antenna unit, the pre-amplifier has an input reflection factor transformed by a length of the cable, the at least one transformation element, or a combination thereof such that the value of the input reflection factor is greater than 0.7, the method comprising:
exciting magnetic resonance signals by the body coil or the at least one local coil;
receiving at least some of the magnetic resonance signals by the body coil; and
amplifying the at least some magnetic resonance signals by the pre-amplification unit with the input reflection factor to provide a detuning effect.

18. The method of claim 17 , wherein the body coil further comprises a high-power impedance, and
wherein, during excitation of the magnetic resonance signals by the at least one local coil, the antenna unit of the body coil is connected to the high-power impedance.

19. The method of claim 17 , wherein signals are received simultaneously by the at least one local coil and the body coil.

20. The method of claim 17 , wherein the body coil further comprises a terminating impedance,
wherein the magnetic resonance signals are excited solely by the body coil,
wherein the receiving of the magnetic resonance signals is by the at least one local coil and the antenna unit of the body coil is connected to the terminating impedance.

Assignees

• Eberler Ludwig
• Matschl Volker
• Nistler Juergen
• Siemens Healthcare Gmbh

Inventors

• Eberler Ludwig
• Matschl Volker
• Nistler Jürgen

Classifications

• G01R33/34069

  Saddle coils · CPC title

• G01R33/34076

  Birdcage coils · CPC title

• G01R33/3614

  RF power amplifiers · CPC title

• G01R33/3453

  Transverse electromagnetic [TEM] coils · CPC title

• A61B5/055 Primary

  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging · CPC title