Diagnostic system using nuclear magnetic resonance phenomenon

• US 5,402,788 A
• Filed: 06/21/1993
• Issued: 04/04/1995
• Est. Priority Date: 06/25/1992
• Status: Expired due to Fees

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Hagiwara, Toshihiko, Tsukaya, Takashi, Matsui, Koichi, Takayama, Shuichi, Hibino, Hiroki, Hayashi, Masaaki, Gotanda, Masakazu, Yamaguchi, Tatsuya, Yoshino, Kenji, Shimizu, Koichi, Hiyama, Keiichi, Fujio, Koji
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Casler, Brian L.
• Application Number:
  US08/080,224
• Time in Patent Office: 652 Days
• Field of Search: 128/653.2, 128/653.5, 128/656, 128/657, 128/658, 128/4, 128/6, 324/322
• US Class Current: 600/423
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: G01R 33/285 Invasive instruments, e.g. catheters or biopsy needles, specially adapted for tracking, guiding or visualization by NMR
• CPC Class Codes: G01R 33/288 Provisions within MR facilities for enhancing safety during MR, e.g. reduction of the specific absorption rate [SAR], detection of ferromagnetic objects in the scanner room
• CPC Class Codes: G01R 33/34084 implantable coils or coils being geometrically adaptable to the sample, e.g. flexible coils or coils comprising mutually movable parts
• CPC Class Codes: G01R 33/3657 Decoupling of multiple RF coils wherein the multiple RF coils do not have the same function in MR, e.g. decoupling of a transmission coil from a receive coil

Abstract

A diagnostic system using a nuclear magnetic resonance phenomenon comprises an external magnetic field generator, provided externally, for generating a magnetic field in a living body, a thin diameter member capable of being inserted into a body cavity and having flexibility, a high frequency coil, provided at a top end of the thin diameter member, for transmitting and receiving a high frequency, a nuclear magnetic resonance signal measuring device for receiving a nuclear magnetic resonance signal from the living body, and a transformer, provided between the high frequency coil and the nuclear magnetic resonance signal measuring device, for electrically isolating and separating the high frequency coil from the nuclear magnetic resonance signal measuring device in a manner such that the nuclear magnetic resonance signal is transmittable between the high frequency coil and the nuclear magnetic resonance signal measuring device.

Claims

1. A diagnostic system using a nuclear magnetic resonance phenomenon, comprising:

an external magnetic field generator, provided externally of a living body, for generating a magnetic field in a living body;

a thin diameter member which is insertable into a body cavity of the living body, and said thin diameter member having flexibility;

a high frequency coil, provided at a top end of said thin diameter member, for transmitting and receiving a high frequency signal;

a nuclear magnetic resonance signal measuring device for receiving a nuclear magnetic resonance signal from the living body; and

isolating and separating means, provided between said high frequency coil and said nuclear magnetic resonance signal measuring device, for electrically isolating and separating said high frequency coil from said nuclear magnetic resonance signal measuring device in a manner such that the nuclear magnetic resonance signal is transmittable between said high frequency coil and said nuclear magnetic resonance signal measuring device.

2. The system according to claim 1, further comprising amplifying means for amplifying the high frequency signal received by said high frequency coil.

3. The system according to claim 2, wherein said isolating and separating means comprises a high frequency transducer having:

a first wire connected to said nuclear magnetic resonance signal measuring device, and

a second wire connected to an output side of said amplifying means and electrically insulated from said first wire.

4. The system according to claim 3, further comprising a stabilizing d.c. power source connected to supply a d.c. bias voltage to said amplifying means.

5. The system according to claim 2, wherein:

said amplifying means comprises a pre-amplifier; and

said isolating and separating means comprises an isolation amplifier provided between said pre-amplifier and said nuclear magnetic resonance signal measuring device.

6. The system according to claim 5, further comprising a stabilizing d.c. power source for supplying a d.c. bias voltage to said pre-amplifier and to said isolation amplifier.

7. The system according to claim 1, wherein said thin diameter member comprises an endoscope.

8. A diagnostic system using a nuclear magnetic resonance phenomenon, comprising:

a control section provided internally of the diagnostic system;

an insertion section of thin diameter, extending from said control section, and being insertable into a body cavity of a living body, and said insertion section having flexibility;

an endoscope having a high frequency antenna provided in said insertion section;

a plurality of magnetic resonance signal measuring devices for processing a nuclear magnetic resonance signal from said high frequency antenna; and

matching means for selectively coupling said high frequency antenna to each of said plurality of magnetic resonance signal measuring devices having a different circuit impedance characteristic.

9. The system according to claim 8, wherein said antenna is a loop antenna, and said matching means includes:

a first variable capacitor connected to said antenna in parallel, and

a second variable capacitor connected to said antenna in series, and

wherein said matching means is arranged to impedance-match said antenna and each of said magnetic resonance signal measuring devices.

10. The system according to claim 9, wherein said matching means further includes a diode arranged in parallel to said loop antenna.

11. The system according to claim 9, wherein said control section includes adjusting means provided in said control section for adjusting a capacity of each of said variable capacitors.

12. The system according to claim 11, wherein each magnetic resonance signal measuring device forms a signal showing a matching state between said matching means and each magnetic resonance signal measuring device when receiving each magnetic resonance signal from said antenna through said matching means.

13. The system according to claim 12, further comprising a controlling device coupled to receive said signal showing the matching state, and to actuate said adjusting means based on said received signal.

14. The system according to claim 8, wherein said matching means is connected to said antenna, and comprises a plurality of pre-amplifiers, each pre-amplifier having a different circuit impedance characteristic, and wherein each of said pre-amplifiers is connectable to each of said magnetic resonance signal measuring devices having a corresponding circuit impedance characteristic.

15. The system according to claim 14, wherein said endoscope comprises:

a universal cord extending from the control section, and

a signal line passage extending to the universal cord from said antenna.

16. The system according to claim 15, wherein said endoscope further comprises:

a light guide, contained in the insertion section, for providing an illumination light to a portion of an object to be examined from an end surface of the insertion section; and

an objective optical system optically coupled to said light guide for receiving light reflected from the portion of the object to be examined, and

wherein said light guide extends to said universal cord from the insertion section.

17. The system according to claim 16, wherein said endoscope further comprises:

an image-forming device, contained in the insertion section, for converting an image corresponding to the light received by said objective optical system to an electrical signal; and

a signal line passage having an end connected to said image-forming device, and extending to an inside portion between said insertion section and said universal cord.