Magnetic resonance imaging apparatus, coil system for a magnetic resonance imaging apparatus and magnetic resonance imaging method

• US 7,391,214 B2
• Filed: 12/26/2006
• Issued: 06/24/2008
• Est. Priority Date: 01/06/2006
• Status: Active Grant

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Original Assignee: Toshiba Medical Systems Corporation (Canon Inc.), Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Adachi, Kohei
• Primary Examiner(s): Shrivastav; Brij B
• Application Number:
  US11/645,004
• Publication Number:
  US 20070176601A1
• Time in Patent Office: 546 Days
• Field of Search: 324300-322, 600407-455, 455/133
• US Class Current: 324/318
• CPC Class Codes: G01R 33/34 Constructional details, e.g. resonators , specially adapted to MR
• CPC Class Codes: G01R 33/341 comprising surface coils
• 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

Abstract

A magnetic resonance imaging apparatus includes a receiver coil, at least one transmitter antenna, receiver antennas, a signal selection unit and a processing unit. The receiver coil receives a nuclear magnetic resonance signal from an object as a reception signal. The transmitter antenna transmits the reception signal by radio. The receiver antennas are arranged to receive the reception signal. The signal selection unit selects a reception signal received by a specific receiver antenna. The processing unit reconstructs an image of the object from the reception signal selected by the signal selection unit.

Claims

1. A magnetic resonance imaging apparatus comprising:

a receiver coil configured to receive a nuclear magnetic resonance signal from an object as a reception signal;

at least one reception signal transmitter antenna configured to transmit the reception signal from said receiver coil by radio;

a plurality of reception signal receiver antennas arranged to receive the reception signal transmitted from said reception signal transmitter antenna;

a signal selection unit configured to select a reception signal received by a specific single reception signal receiver antenna of said plural reception signal receiver antennas; and

a reception data processing unit configured to reconstruct an image of the object from the reception signal selected by said signal selection unit.

2. A magnetic resonance imaging apparatus according to claim 1, wherein:

said reception signal receiver antennas are arranged in at least a direction in which a table for setting the object moves and

said signal selection unit is configured to select a reception signal received by a reception signal receiver antenna close to said reception signal transmitter antenna.

3. A magnetic resonance imaging apparatus according to claim 1, further comprising:

a moving unit configured to move said receiver coil; and

a coil position estimating unit configured to estimate a position of said receiver coil,

wherein said signal selection unit is configured to select a reception signal received by a reception signal receiver antenna close to said reception signal transmitter antenna based on the position of said receiver coil estimated by said coil position estimating unit.

4. A magnetic resonance imaging apparatus according to claim 1, further comprising:

a table moving unit configured to move said receiver coil with a table for setting the object; and

a coil position estimating unit configured to estimate a position of said receiver coil based on a distance by which the table moved,

wherein said signal selection unit is configured to select a reception signal received by a reception signal receiver antenna close to said reception signal transmitter antenna based on the position of said receiver coil estimated by said coil position estimating unit.

5. A magnetic resonance imaging apparatus according to claim 1, wherein:

said receiver coil includes element coils,

further comprising;

a frequency control unit configured to control frequencies of reception signals received by said element coils respectively to make the reception signals showing mutually different frequency bands without overlapping; and

a signal compounding unit configured to compound the reception signals so as to multiplex the reception signals from corresponding reception signal transmitter antennas,

wherein said frequency control unit is configured to control the frequencies of the reception signals so as to tune the frequency bands of the reception signals multiplexed from the reception signal transmitter antennas to said reception signal receiver antennas.

6. A magnetic resonance imaging apparatus according to claim 1, wherein:

said receiver coil includes element coils,

further comprising;

a frequency control unit configured to control frequencies of reception signals received by said element coils respectively to transmit the reception signals showing mutually different frequency bands without overlapping from reception signal transmitter antennas respectively, said frequency control unit being configured to control the frequencies of the reception signals so as to tune the frequencies to reception signal receiver antennas close to the reception signal transmitter antennas.

7. A magnetic resonance imaging apparatus according to claim 6, further comprising:

a moving unit configured to move said receiver coil;

a coil position estimating unit configured to estimate a position of said receiver coil; and

a frequency data transmitting unit configured to detect the reception signal receiver antennas close to the reception signal transmitter antennas based on the position of said receiver coil estimated by said coil position estimating unit and transmit frequency data tuning to the detected reception signal receiver antennas to said frequency control unit,

wherein said frequency control unit is configured to control the frequencies of the reception signals so as to tune the frequencies to the reception signal receiver antennas close to the reception signal transmitter antennas according to the frequency data obtained from said frequency data transmitting unit.

8. A magnetic resonance imaging apparatus according to claim 5, further comprising a synchronizing unit configured to synchronize the reception signals transmitted with frequency conversion by radio.

9. A magnetic resonance imaging apparatus according to claim 6, further comprising a synchronizing unit configured to synchronize the reception signals transmitted with frequency conversion by radio.

10. A magnetic resonance imaging apparatus according to claim 1, wherein said reception signal receiver antennas are arranged in a vicinity of an end part of an inside of a static field magnet.

11. A coil system for a magnetic resonance imaging apparatus comprising:

a receiver coil configured to receive a nuclear magnetic resonance signal from an object as a reception signal;

at least one reception signal transmitter antenna configured to transmit the reception signal from said receiver coil by radio;

a plurality of reception signal receiver antennas arranged to receive the reception signal transmitted from said reception signal transmitter antenna; and

a signal selection unit configured to select a reception signal received by a specific single reception signal receiver antenna of said plural reception signal receiver antennas.

12. A magnetic resonance imaging method comprising:

receiving a nuclear magnetic resonance signal from an object as a reception signal;

transmitting the received reception signal by radio;

receiving the reception signal transmitted by radio by a plurality of reception signal receiver antennas;

selecting a reception signal received by a specific single reception signal receiver antenna of the plural reception signal receiver antennas; and

reconstructing an image of the object from the selected reception signal.

13. A magnetic resonance imaging method comprising:

receiving a nuclear magnetic resonance signal at an MRI RF coil from an object as a reception signal;

wirelessly transmitting the reception signal from said MRI RF coil;

receiving the transmitted reception signal at a plurality of reception signal sites;

selecting a reception signal received by a specific single reception signal site of said plural reception signal sites; and

reconstructing an image of the object from the selected reception signal.

14. A method as in claim 13 wherein:

said receiving step is performed by plural receiver RF antennas arranged in at least one direction in which a table for positioning the object moves and

said selecting step includes selecting a reception signal received by a receiver RF antenna positioned relatively closer to the source of said transmitted reception signal than others of said antennas.

15. A method as in claim 13 further comprising:

moving said MRI RF coil; and

estimating the position of said MRI RF coil;

wherein said selecting step includes selecting a signal received by one of plural signal receiver antennas that is nearest to an RF transmitter antenna based on the estimated position of the MRI RF coil and which is wirelessly transmitting the reception signal from the MRI RF coil.

16. A method as in claim 13 further comprising:

moving said MRI RF coil with a table for positioning the object; and

estimating a position of said MRI RF coil based on a distance by which the table moves,

wherein said signal selecting step is based on the estimated position of said MRI RF coil.

17. A method as in claim 13 further comprising:

controlling re-transmission RF frequencies of reception signals received by each of plural sub-element coils of said MRI RF coil respectively to make the reception signals for such sub-element coils occupy mutually different non-overlapping RF frequency bands; and

multiplexing MRI RF reception signals from MRI RF coil sub-element transmitter antennas,

wherein the frequency bands are multiplexed from MRI RF coil sub-element transmitter antennas to respectively corresponding signal receiver antennas.

18. A method as in claim 13 wherein:

re-transmission frequencies of MRI signals received by sub-element coils of the MRI RF coil are controlled to occupy respectively different non-overlapping frequency bands when transmitted by respectively corresponding transmitter antennas, said frequency bands being controlled so as to tune them to be received by receiver antennas disposed closest the respective transmitter antennas.

19. A method as in claim 18 further comprising:

moving said MRI RF coil;

estimating a position of said MRI RF coil; and

detecting those reception signal receiver antennas disposed relatively closest to MRI RF coil transmitter antennas based on the estimated position of the MRI RF coil and transmitting data for frequency tuning such detected closest reception signal receiver antennas;

wherein the frequency bands of the transmitted MRI RF coil signals are respectively tuned based on the transmitted data for frequency tuning to a reception frequency band corresponding to a reception signal receiver antenna disposed closest to a corresponding MRI RF coil signal transmitter antenna.

20. A method as in claim 17 further comprising synchronizing MRI RF coil signals transmitted with frequency conversion by radio.

21. A method as in claim 18 further comprising synchronizing MRI RF coil signals transmitted with frequency conversion by radio.

22. A method as in claim 13 wherein reception signal receiver antennas are arranged at an inside end portion of a static field magnet of an MRI system.

23. A method for conveying MRI NMR signals during a magnetic resonance imagine process, said method comprising:

receiving MRI nuclear magnetic resonance (NMR) signals from an object at an MRI RF coil;

wirelessly transmitting the NMR signals from at least one location;

receiving the transmitted NMR signal from said transmitter location at a plurality of reception signal locations; and

selecting for further MRI processing the NMR MRI signals received by a specific single one of said plural reception signal locations.