MAGNETIC RESONANCE IMAGING APPARATUS

• US 20100117649A1
• Filed: 11/09/2009
• Published: 05/13/2010
• Est. Priority Date: 11/11/2008
• Status: Active Grant

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kasami, Hideo, Nakanishi, Toshiyuki, Sekiguchi, Takahiro, Akita, Koji
• Granted Patent: US 8,502,540 B2
• Time in Patent Office: Days
• US Class Current: 324/318
• 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 33/3692 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

An apparatus including a probe unit and a control/imaging unit, the probe unit including a converter converting a sampled magnetic-resonance signal into a digital signal, a first transmitter converting the digital signal into a first-radio signal, a first receiver receiving a second-radio signal, and performing detection on the second-radio signal to obtain a first-received signal, and a clock-regeneration unit regenerating a clock component from the first-received signal to generate a regenerated-clock signal, the control/imaging unit including a second-receiver receiving the first-radio signal to obtain a second-received signal, a data processor performing data processing on the second-received signal in synchronism with a reference-clock signal to obtain a video signal, and a second transmitter including a modulator modulating a carrier wave using the reference-clock signal, the second transmitter converting the reference-clock signal into the second-radio signal and transmitting the second-radio signal through the second-wireless channel.

Claims

1. A magnetic resonance imaging apparatus comprising a probe unit and a control/imaging unit,

the probe unit including:

a probe which detects a magnetic resonance signal in a subject;

an analog-to-digital converter which samples the magnetic resonance signal using a sampling clock signal, and converts the sampled magnetic resonance signal into a digital signal;

a first transmitter which converts the digital signal into a first radio signal and transmits the first radio signal through a first wireless channel;

a first receiver which receives a second radio signal transmitted through a second wireless channel, and performs detection on the second radio signal to obtain a first received signal; and

a clock regeneration unit configured to regenerate a clock component from the first received signal to generate a regenerated clock signal to be used as a base signal for the sampling clock signal,

the control/imaging unit including;

a second receiver which receives the first radio signal to obtain a second received signal;

a clock generator which generates a reference clock signal;

a data processor which performs data processing on the second received signal in synchronism with the reference clock signal to obtain a video signal, the data processing including image reconstruction processing; and

a second transmitter including a modulator which modulates a carrier wave using the reference clock signal, the second transmitter converting the reference clock signal into the second radio signal and transmitting the second radio signal through the second wireless channel.

2. The apparatus according to claim 1, wherein

the first receiver receives the first radio signal using a receiving antenna provided on a bed which is movable with the subject mounted thereon;

the second transmitter transmits the second radio signal using a transmitting antenna fixed in position; and

the clock generator compensates for a phase of the reference clock signal when a distance between the receiving antenna and the transmitting antenna varies.

3. The apparatus according to claim 1, wherein

the first receiver receives the first radio signal using a receiving antenna provided on a bed which is movable with the subject mounted thereon;

the second transmitter transmits the second radio signal using a transmitting antenna fixed in position;

the control/imaging unit further includes a position control unit configured to control a position of the bed and output coordinate information indicating the position of the bed, and a phase calculation unit configured to calculate a change in a distance between the receiving antenna and the transmitting antenna using the coordinate information, and calculate a phase shift corresponding to the change; and

the clock generator adjusts a phase of the reference clock signal by the phase shift to compensate for the phase of the reference clock signal when the distance between the receiving antenna and the transmitting antenna varies.

4. The apparatus according to claim 1, wherein

the first receiver receives the first radio signal using a receiving antenna fixed in position;

and

the second transmitter transmits the second radio signal using a transmitting antenna fixed in position.

5. A magnetic resonance imaging apparatus comprising a probe unit and a control/imaging unit,

the probe unit including:

a probe which detects a magnetic resonance signal in a subject;

an analog-to-digital converter which samples the magnetic resonance signal using a sampling clock signal, and converts the sampled magnetic resonance signal into a first digital signal;

a pre-transmission processor which performs pre-transmission processing on the first digital signal in synchronism with a first processing clock signal to obtain a second digital signal;

a first transmitter which converts the second digital signal into a first radio signal and transmits the first radio signal through a first wireless channel;

a first receiver which receives a second radio signal transmitted through a second wireless channel, and performs detection on the second radio signal to obtain a first received signal;

a clock regeneration unit configured to regenerate a clock component from the first received signal to generate a regenerated clock signal; and

a first multiplier which multiplies the regenerated clock signal by preset values to generate the sampling clock signal and the first processing clock signal,

the control/imaging unit including;

a second receiver which receives the first radio signal to obtain a second received signal;

a clock generator which generates a reference clock;

a second multiplier which multiplies the reference clock signal by a first preset value to generate a second processing clock signal;

a data processor which performs data processing on the second received signal using the second processing clock signal to obtain a magnetic resonance imaging signal, the data processing including image reconstruction processing; and

a second transmitter including a modulator which modulates a carrier wave using the reference clock signal, the second transmitter converting the reference clock signal into the second radio signal and transmitting the second radio signal through the second wireless channel.

6. The apparatus according to claim 5, wherein

the first multiplier also multiplies the regenerated clock signal by a second preset value to generate a first conversion clock signal;

and

the probe unit further includes an analog processor including a first frequency converter interposed between the probe and the analog-to-digital converter, the first frequency converter converting a frequency of the magnetic resonance signal using the first conversion clock signal.

7. The apparatus according to claim 5, wherein

the first multiplier also multiplies the regenerated clock signal by a third preset value to generate a second conversion clock signal;

and

the first transmitter includes a second frequency converter which converts a frequency of the second digital signal using the second conversion clock signal, to generate the first radio signal.

8. The apparatus according to claim 5, wherein

the second multiplier also multiplies the reference clock signal by a fourth preset value to generate a third conversion clock signal;

and

the second receiver includes a third frequency converter which converts a frequency of the first digital signal using the third conversion clock signal, to generate the second received signal.

9. The apparatus according to claim 5, wherein

the second multiplier also multiplies the reference clock signal by a fifth preset value to generate a fourth conversion clock signal;

and

the second transmitter includes a second frequency converter which converts a frequency of the reference clock signal using the fourth conversion clock signal, to generate the first radio signal.

10. The apparatus according to claim 5, wherein the reference clock signal has a frequency equal to or less than a minimum frequency of the first processing clock signal, and is in phase with the first processing clock signal.

11. The apparatus according to claim 5, wherein

the first receiver receives the first radio signal using a receiving antenna provided on a bed which is movable with the subject mounted thereon;

the second transmitter transmits the second radio signal using a transmitting antenna fixed in position; and

the clock generator compensates for a phase of the reference clock signal when a distance between the receiving antenna and the transmitting antenna varies.

12. The apparatus according to claim 5, wherein

the first receiver receives the first radio signal using a receiving antenna provided on a bed which is movable with the subject mounted thereon;

the second transmitter transmits the second radio signal using a transmitting antenna fixed in position;

the control/imaging unit further includes a position control unit configured to control a position of the bed and output coordinate information indicating the position of the bed, and a phase calculation unit configured to calculate a change in a distance between the receiving antenna and the transmitting antenna using the coordinate information, and calculate a phase shift corresponding to the change; and

the clock generator adjusts a phase of the reference clock signal by the phase shift to compensate for the phase of the reference clock signal when the distance between the receiving antenna and the transmitting antenna varies.

13. The apparatus according to claim 5, wherein

the first receiver receives the first radio signal using a receiving antenna fixed in position;

and

the second transmitter transmits the second radio signal using a transmitting antenna fixed in position.