Arrangement to transmit magnetic resonance signals

• US 8,055,196 B2
• Filed: 05/13/2009
• Issued: 11/08/2011
• Est. Priority Date: 05/14/2008
• Status: Active Grant

• Current Assignee: Siemens Healthineers AG (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Biber, Stephan, Vester, Markus, Bollenbeck, Jan, Oppelt, Ralph
• Primary Examiner(s): Donovan; Lincoln
• Assistant Examiner(s): COLE, BRANDON S
• Application Number:
  US12/465,147
• Publication Number:
  US 20090286478A1
• Time in Patent Office: 909 Days
• Field of Search: 455 39- 48, 455 59- 90
• US Class Current: 455/41.2
• CPC Class Codes: G01R 33/3415 comprising arrays of sub-coils , i.e. phased-array coils with flexible receiver channels
• 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
• CPC Class Codes: G01R 33/3664 Switching for purposes other than coil coupling or decoupling, e.g. switching between a phased array mode and a quadrature mode, switching between surface coil modes of different geometrical shapes, switching from a whole body reception coil to a local reception coil or switching for automatic coil selection in moving table MR or for changing the field-of-view G01R33/3671 takes precedence

Abstract

An arrangement for transmitting magnetic resonance signals, with a transmission link that connects a local coil with a receiver, has a first channel of the local coil with a first single antenna to acquire a first magnetic resonance signal, as well as a first mixer connected with the first single antenna. The first mixer forms an intermediate-frequency first signal from the supplied first magnetic resonance signal. A second channel of the local coil has a second single antenna to acquire a second magnetic resonance signal, as well as a second mixer connected with the second single antenna. The second mixer forms an intermediate-frequency second signal from the supplied second magnetic resonance signal. The local coil has a device for signal combination that, by frequency multiplexing, that combines the intermediate-frequency first signal of the first channel and the intermediate-frequency second signal of the second channel so that it arrives at the receiver via the transmission path. The receiver has an A/D converter at which one of the transmitted intermediate-frequency signals of an associated channel arrives in order to be sampled with a sampling frequency for digitization. For frequency conversion, a first local oscillator frequency is connected at the first mixer and a second local oscillator frequency is connected at the second mixer. the first and second local oscillator frequencies are selected such that intermediate-frequencies formed by the frequency conversion are mirror-symmetrical relative to the sampling frequency of the A/D converter.

Claims

1. An arrangement for transmitting magnetic resonance signals comprising:

a local coil configured to receive analog magnetic resonance signals;

a receiver configured to convert said analog magnetic resonance signals into digital signals;

a transmission link placing said local coil in communication with said receiver to transmit said analog magnetic resonance signals to said receiver;

said local coil comprising a first channel comprising a first single antenna that acquires a first analog magnetic resonance signal, and a first mixer connected to said first single antenna, said first mixer being configured to form an intermediate-frequency first analog signal from said first analog magnetic resonance signal;

said local coil comprising a second channel comprising a second single antenna configured to receive a second analog magnetic resonance signal, and a second mixer connected to said second single antenna, said second mixer forming an intermediate frequency second analog signal from said second analog magnetic resonance signal;

said local coil comprising a signal combiner configured to combine said intermediate frequency first analog signal of said first channel and said intermediate frequency second analog signal of said second channel by frequency multiplexing to produce said analog magnetic resonance signal that is communicated via said transmission link to said receiver;

said receiver comprising an analog-to-digital converter that samples the transmitted intermediate frequency signals with a sampling frequency to produce said digital signal;

for frequency conversion into a first intermediate frequency range, said first mixer being supplied with a first local oscillator signal, and for frequency conversion into a second intermediate frequency range, said second mixer being supplied with a second local oscillator frequency; and

said first and second local oscillator frequency respectively causing the respective intermediate frequencies formed by the frequency conversion in the first and second mixers to be mirror symmetric relative to said sampling frequency of said analog-to-digital converter.

2. Arrangement according to claim 1, wherein

the first local oscillator frequency is selected below a frequency of the acquired magnetic resonance signals, such that a down-mixing of the first magnetic resonance signal ensues in an uninverted state and

the second local oscillator frequency is selected above a frequency of the acquired magnetic resonance signals, such that a down-mixing of the second magnetic resonance signal ensues in an inverted state.

3. Arrangement according to claim 1, wherein the device for signal combination is connected on the input side with associated outputs of the modulators and on the output side with the transmission link, such that an intermediate-frequency transmission signal is formed from the intermediate-frequency signals of the channels and transmitted to the receiver.

4. Arrangement according to claim 3 wherein the device for signal combination is designed as a diplex filter.

5. Arrangement according to claim 3 wherein the receiver possesses a device for signal splitting that forms from the received intermediate-frequency transmission signal an intermediate-frequency first signal that can be associated with the first channel an intermediate-frequency second signal that can be associated with the second channel.

6. Arrangement according to claim 5 wherein

the device for signal splitting is connected on the output side with an A/D converter associable with the first channel, such that the intermediate-frequency first signal associable with the first channel is sampled with the sampling frequency, and

the device for signal splitting is connected on the output side with an A/D converter associable with the second channel, such that the intermediate-frequency second signal associable with the second channel is sampled with the sampling frequency.

7. Arrangement according to claim 5 wherein the device for signal splitting is designed as a diplex filter or as an modulator.

8. Arrangement according to claim 3, wherein the receiver comprises a multiplexer supplied at an input side thereof with the intermediate-frequency transmission signal transmitted by frequency multiplexing, said multiplexer being connected at an output side thereof with the A/D converter (ADWE61).

9. Arrangement according to claim 1, comprising at least one of an amplifier or a bandpass filter interposed between the single antenna and the mixer.