SIMULTANEOUS TX-RX FOR ANTENNA DEVICES

• US 20150338478A1
• Filed: 08/04/2015
• Published: 11/26/2015
• Est. Priority Date: 02/28/2011
• Status: Active Grant

• Current Assignee: Life Services, LLC
• Original Assignee: Life Services, LLC
• Inventors: Schillak, Scott M., Vaughan, John Thomas Jr., Lemaire, Charles A., Waks, Matthew T.
• Granted Patent: US 10,627,463 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 33/3614 RF power amplifiers
• 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 33/3692 involving signal transmission without using electrically conductive connections, e.g. wireless communication or optical communication of the MR signal or an auxiliary signal other than the MR signal
• CPC Class Codes: G01R 33/54 Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console

Abstract

Apparatus and method that are more efficient and flexible, and obtain and connect high-power RF transmit signals (TX) to RF-coil devices in an MR machine or other devices and simultaneously receive signals (RX) and separate net receive signals NRX) of interest by subtracting or filtering to remove the subtractable portion of the transmit signal (STX) from the RX and preamplifying the NRX and signal processing the preamplified NRX. In some embodiments, signal processing further removes artifacts of the transmitted signal, e.g., by digitizing the NRX signal, storing the digitized NRX signal in a memory, and performing digital signal processing. In some embodiments, the present invention also includes pre-distorting the TX signals in order to be better able to identify and/or remove the remaining artifacts of the transmitted signal from the NRX signal. This solution also applies to other high-power RF-transmit-antennae signals.

Claims

1. A method comprising:

generating a generated RF pulse-sequence (RFPS) signal;

preprocessing the RFPS signal using a set of one or more transmit-preprocessing parameters to form a preprocessed transmit (PTX) signal;

amplifying the PTX signal to form a power-amplified TX signal;

transmitting the power-amplified TX signal from a set of one or more transmit-antenna elements;

receiving a receive (RX) signal from a set of one or more receive-antenna elements;

post-processing the obtained RX signal using a set of one or more receive-post-processing parameters to obtain a net received (NRX) signal;

analyzing the NRX signal to determine whether the NRX signal is satisfactory;

when the analyzing determines that the NRX signal is satisfactory, forming a magnetic resonance (MR) image; and

when the analyzing determines that the NRX signal is not satisfactory, adjusting at least one of the set of preprocessing parameters and repeating the preprocessing, amplifying, transmitting, receiving, post-processing, and analyzing of the generated RFPS signal.

2. The method of claim 1, wherein the receiving of the RX signal occurs simultaneously with the transmitting of the power-amplified TX signal.

3. The method of claim 1, wherein the set of one or more receive-antenna elements are part of an MRI coil, wherein the transmitting of the power-amplified TX signal from the set of one or more transmit-antenna elements and the receiving of the RX signal from the set of the one or more receive-antenna elements occur simultaneously.

4. The method of claim 1, wherein the preprocessing of the RFPS signal includes frequency filtering the RFPS signal, and wherein the adjusting of the preprocessing parameter includes adjusting a frequency-filtering parameter.

5. The method of claim 1, further comprising:

automatically adjusting a resonant frequency and impedance of the set of one or more transmit-antenna elements.

6. The method of claim 1, further comprising:

automatically adjusting a resonant frequency and impedance of the set of one or more receive-antenna elements.

7. The method of claim 1, further comprising:

automatically adjusting a resonant frequency and impedance of the set of one or more transmit-antenna elements; and

automatically adjusting a resonant frequency and impedance of the set of one or more receive-antenna elements.

8. The method of claim 1, wherein the RFPS signal has a power of less than one watt and the power-amplified TX signal has a power of at least 100 watts.

9. The method of claim 1, wherein the RFPS signal has a power of less than one watt and the power-amplified TX signal has a power of at least 1000 watts.

10. The method of claim 1,

wherein the preprocessing of the RFPS signal includes actively adjusting a gain and phase of the RFPS signal,

wherein the transmitting of the power-amplified TX signal includes coupling the power-amplified TX signal to a plurality of the set of one or more transmit-antenna elements,

wherein the post-processing of the obtained RX signal includes:

actively adjusting gains, phases, and signal combinations of the obtained RX signal,

generating a subtractable version of the transmit (STX) signal, and

subtracting the STX signal from the obtained RX signal to obtain the NRX signal, and

wherein the RFPS signal has a power of less than one watt and the power-amplified TX signal has a power of at least 100 watts.

11. An apparatus comprising:

means for generating a generated RF pulse-sequence (RFPS) signal;

means for preprocessing the RFPS signal using a set of one or more transmit-preprocessing parameters to form a preprocessed transmit (PTX) signal;

means for amplifying the PTX signal to form a power-amplified TX signal;

means for transmitting the power-amplified TX signal;

means for receiving a receive (RX) signal;

means for post-processing the obtained RX signal using a set of one or more receive-post-processing parameters to obtain a net received (NRX) signal;

means for analyzing the NRX signal to determine whether the NRX signal is satisfactory;

means for forming a magnetic resonance (MR) image when the means for analyzing determines that the NRX signal is satisfactory; and

means for adjusting at least one of the set of preprocessing parameters when the analyzing determines that the NRX signal is not satisfactory, and for repeating the preprocessing, amplifying, transmitting, receiving, post-processing, and analyzing of the generated RFPS signal.

12. The apparatus of claim 11, wherein the means for receiving the RX signal receives the RX signal simultaneously with transmitting of the power-amplified TX signal from the means for transmitting.

13. The apparatus of claim 11, wherein the means for receiving are part of an MRI coil, wherein transmitting from the means for transmitting and receiving of the RX signal from the means for receiving occur simultaneously.

14. The apparatus of claim 11, wherein the means for preprocessing the RFPS signal includes means for frequency filtering the RFPS signal.

15. The apparatus of claim 11, further comprising means for adjusting a resonant frequency and impedance of the means for transmitting.

16. The apparatus of claim 11, further comprising means for adjusting a resonant frequency and impedance of the means for receiving.

17. A method comprising:

generating a transmit (TX) signal;

forming an adjusted TX signal, wherein the forming of the adjusted TX signal includes actively adjusting a gain and phase of the TX signal;

transmitting the adjusted TX signal from a plurality of transmit antenna elements;

receiving a plurality of receive (RX) signals;

forming an adjusted RX signal, wherein the forming of the adjusted RX signal includes actively adjusting gains and phases of the plurality of RX signals;

generating a subtractable version of the transmit (STX) signal; and

subtracting the STX signal from the adjusted RX signal to obtain a net received signal (NRX).

18. The method of claim 17, wherein the forming of the adjusted TX signal further includes actively adjusting a frequency of the TX signal.

19. The method of claim 17, wherein the forming of the adjusted RX signal further includes actively adjusting a signal combination of the plurality of RX signals.

20. The method of claim 17, wherein the forming of the adjusted TX signal includes power amplifying the adjusted TX signal, and wherein the method further includes:

analyzing the NRX signal to determine whether the NRX signal is satisfactory;

when the analyzing determines that the NRX signal is satisfactory, forming a magnetic resonance (MR) image;

when the analyzing determines that the NRX signal is not satisfactory, adjusting at least one of a set of preprocessing parameters and iterating the method; and

wherein the TX signal has a power of less than one watt and the power-amplified TX signal has a power of at least 1000 watts.