Method and arrangement to transmit magnetic resonance signals

• US 8,390,292 B2
• Filed: 02/12/2010
• Issued: 03/05/2013
• Est. Priority Date: 02/12/2009
• Status: Active Grant

• Current Assignee: Siemens Healthcare GMBH (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Bollenbeck, Jan
• Primary Examiner(s): ARANA, LOUIS M
• Application Number:
  US12/704,697
• Publication Number:
  US 20100201365A1
• Time in Patent Office: 1,117 Days
• Field of Search: 324/322, 324/318, 324/307, 324/309, 324/300
• US Class Current: 324/322
• CPC Class Codes: G01R 33/341 comprising surface coils
• CPC Class Codes: G01R 33/3607 RF waveform generators, e.g. frequency generators, amplitude-, frequency- or phase modulators or shifters, pulse programmers, digital to analog converters for the RF signal, means for filtering or attenuating of the RF signal
• CPC Class Codes: G01R 33/3621 NMR receivers or demodulators, e.g. preamplifiers, means for frequency modulation of the MR signal using a digital down converter, means for analog to digital conversion [ADC] or for filtering or processing of the MR signal such as bandpass filtering, resampling, decimation or interpolation
• CPC Class Codes: G01R 33/3635 Multi-frequency operation

Abstract

In a method and an arrangement for magnetic resonance signal transmission, a first channel of a local coil arrangement has a first individual antenna that receives a first magnetic resonance signal, and a first frequency converter connected with the first individual antenna, and the first frequency converter forms a first signal with the first magnetic resonance signal supplied thereto and a first oscillator signal supplied thereto. A second channel of the local coil arrangement has a second individual antenna that receives a second magnetic resonance signal, and a second frequency converter connected with the second individual antenna, and the second frequency converter forms a second signal from the second magnetic resonance signal supplied thereto and a second oscillator signal supplied thereto. The local coil arrangement has a signal combination device that applies the first signal and the second signal to a single transmission path. At least one of the oscillator signals has a frequency that corresponds to the difference between the frequency of a first synthesizer frequency signal and the frequency of a second synthesizer frequency signal that are supplied to the local coil arrangement.

Claims

1. A circuit for transmitting magnetic resonance signals comprising:

a magnetic resonance local coil assembly comprising a plurality of channels;

a first of said channels comprising a first individual antenna configured to receive a first magnetic resonance signal and a first frequency converter connected to said first individual antenna, said first frequency converter being configured to form a first signal from said first magnetic resonance signal and a first oscillator signal supplied to said first frequency converter;

a second of said channels comprising a second individual antenna configured to receive a second magnetic resonance signal and a second frequency converter connected to said second individual antenna, said second frequency converter being configured to form a second signal from said second magnetic resonance signal and a second oscillator signal supplied to said second frequency converter;

a signal combiner supplied with said first signal and said second signal that applies both of said first signal and said second signal to a single transmission path forming an output of said local coil assembly;

a first input to said local coil assembly to which a first synthesizer signal is supplied, said first synthesizer signal having a first synthesizer signal frequency;

a second input to said local coil assembly to which a second synthesizer is supplied, said second synthesizer signal having a second synthesizer signal frequency; and

an oscillator signal source in said local coil assembly connected to said first and second inputs, said oscillator signal source supplying said first oscillator signal to said first frequency converter and supplying said second oscillator signal to said second frequency converter, and said oscillator signal source being configured to form at least one of said first and second oscillator signals with an oscillator signal frequency that is a difference between said first synthesizer signal frequency and said second synthesizer signal frequency, said first and second synthesizer signal frequencies being set so that said difference, corresponding to said oscillator signal frequency, allows said first and second signals to both be transmitted via said single transmission path.

2. A circuit as claimed in claim 1 comprising a third input to said local coil assembly to which a third synthesizer signal is supplied, said third synthesizer signal having a third synthesizer signal frequency, and wherein said oscillator signal source is configured to generate the other of said first and second oscillator signals, other than said one of said first and second oscillator signals, with an oscillator signal frequency that is a difference between said first synthesizer signal frequency and said third synthesizer signal frequency.

3. A circuit as claimed in claim 1 comprising respective coaxial cables connected to said first and second inputs, via which said first synthesizer signal and said second synthesizer signal are supplied respectively to said first and second inputs.

4. A circuit as claimed in claim 1 comprising a low pass filter connected between said oscillator signal source and said first and second frequency converters.

5. A circuit as claimed in claim 1 wherein said oscillator signal source has an oscillator signal source output at which both of said first and second oscillator signals are present, and comprising a diplexer connected between said output of said oscillator signal source and said first and second frequency converters that supplies said first oscillator signal only to said first frequency converter and that supplies said second oscillator signal only to said second frequency converter.

6. A circuit as claimed in claim 1 comprising a receiver connected to said single transmission path that receives said first and second signals via said single transmission path.

7. A circuit as claimed in claim 6 wherein said receiver comprises a signal splitter connected to said single transmission path configured to separate said first and second signals from each other.

8. A circuit as claimed in claim 1 wherein said signal combiner is a diplex filter.

9. A method for transmitting magnetic resonance signals in a magnetic resonance local coil assembly comprising a plurality of channels, said method comprising the steps of;

in a first of said channels, receiving a first magnetic resonance signal with a first individual antenna and supplying said first magnetic resonance signal to a first frequency converter connected to said first individual antenna, and in said first frequency converter, forming a first signal from said first magnetic resonance signal and a first oscillator signal supplied to said first frequency converter;

in a second of said channels, receiving a second magnetic resonance signal with a second individual antenna and supplying said second magnetic resonance signal to a second frequency converter connected to said second individual antenna, and in said second frequency converter, forming a second signal from said second magnetic resonance signal and a second oscillator signal supplied to said second frequency converter;

combining said first signal and said second signal and applying both of said first signal and said second signal to a single transmission path forming an output of said local coil assembly;

at a first input to said local coil assembly, supplying a first synthesizer signal, said first synthesizer signal having a first synthesizer signal frequency;

at a second input to said local coil assembly, supplying a second synthesizer, said second synthesizer signal having a second synthesizer signal frequency; and

from an oscillator signal source in said local coil assembly connected to said first and second inputs, supplying said first oscillator signal to said first frequency converter and supplying said second oscillator signal to said second frequency converter, and in said oscillator signal source, forming at least one of said first and second oscillator signals with an oscillator signal frequency that is a difference between said first synthesizer signal frequency and said second synthesizer signal frequency, and setting said first and second synthesizer signal frequencies so that said difference, corresponding to said oscillator signal frequency, allows said first and second signals to both be transmitted via said single transmission path.

10. A method as claimed in claim 9 comprising, at a third input to said local coil assembly, supplying a third synthesizer signal, said third synthesizer signal having a third synthesizer signal frequency, and in said oscillator signal source, generating the other of said first and second oscillator signals, other than said one of said first and second oscillator signals, with an oscillator signal frequency that is a difference between said first synthesizer signal frequency and said third synthesizer signal frequency.

11. A method as claimed in claim 9 comprising supplying said first synthesizer signal and said second synthesizer signal to said first and second inputs via respective coaxial cables.

12. A method as claimed in claim 9 comprising low pass filtering an output of said oscillator signal source.

13. A method as claimed in claim 9 wherein said oscillator signal source has an oscillator signal source output at which both of said first and second oscillator signals are present, and comprising connecting a diplexer between said output of said oscillator signal source and said first and second frequency converters and, via said diplexer, supplying said first oscillator signal only to said first frequency converter and supplying said second oscillator signal only to said second frequency converter.

14. A method as claimed in claim 9 comprising connecting a receiver to said single transmission path that receives said first and second signals via said single transmission path.

15. A method as claimed in claim 14 comprising, in said receiver, connecting a signal splitter to said single transmission path that separates said first and second signals from each other.

16. A method as claimed in claim 9 comprising combining said signals in a diplex filter in said local coil assembly.