Magnetic resonance imaging apparatus for detecting magnetic resonance signals by radio frequency receiving coils

• US 5,951,474 A
• Filed: 02/24/1997
• Issued: 09/14/1999
• Est. Priority Date: 04/26/1996
• Status: Expired due to Term

• Current Assignee: Hitachi Medical Corporation (Hitachi, Ltd.)
• Original Assignee: Hitachi Medical Corporation (Hitachi, Ltd.)
• Inventors: Takahashi, Tetsuhiko, Matsunaga, Yoshikuni
• Primary Examiner(s): Jaworski, Francis J.
• Assistant Examiner(s): MANTIS MERCADER, ELENI M
• Application Number:
  US08/804,925
• Time in Patent Office: 932 Days
• Field of Search: 128/653.2, 128/653.5, 324/318, 324/322, 600/410, 600/422
• US Class Current: 600/422
• CPC Class Codes: G01R 33/34061 Helmholtz coils
• CPC Class Codes: G01R 33/3415 comprising arrays of sub-coils , i.e. phased-array coils with flexible receiver channels
• CPC Class Codes: G01R 33/3678 involving quadrature drive or detection, e.g. a circularly polarized RF magnetic field

Abstract

RF receiving coil device used in a magnetic resonance imaging apparatus capable of acquiring a tomographic image of an object under examination positioned in a static magnetic field along a predetermined direction including quadrature detection coils for detecting an MR signal component along a direction perpendicular to a body axis direction of the object under examination and also perpendicular to a direction of the static magnetic field, and for detecting another MR-signal component along the body axis direction.

Claims

1. A magnetic resonance imaging apparatus comprising a static magnetic field generator disposed on both sides of an object sandwiched therebetween for generating a vertical static magnetic field in a direction perpendicular to a body axis of said object, an RF transmitting coil device for transmitting a radio frequency signal to said object, and an RF receiving coil device for receiving a magnetic resonance signal from said object, wherein said RF receiving coil comprises:

a pair of quadrature detection coils arranged so as to detect an MR signal component along a direction of said body axis and along a direction perpendicular to any direction of said body axis and said vertical static magnetic field direction; and

one of said pair of quadrature detection coils being arranged to be opposite to another of said pair of quadrature detection coils so that said quadrature detection coils sandwich a region of interest of said object, and said quadrature detection coils being arranged to have an extension direction in parallel with said body axis direction and perpendicular to said vertical static magnetic field direction.

2. A magnetic resonance imaging apparatus as claimed in claim 1, wherein said quadrature detection coils include:

a rectangular coil arranged so as to detect the MR signal component along the direction perpendicular to any directions of said body axis and perpendicular to said static magnetic field direction; and

a butterfly type coil arranged so as to detect the MR signal component along the body axis direction.

3. A magnetic resonance imaging apparatus as claimed in claim 2, wherein said butterfly type coil is made of a conductor forming an 8-shaped coil having two loops coupled together, and an intersecting portion of said two loops contains two conductors extended substantially parallel to each other along said vertical magnetic field direction.

4. A magnetic resonance imaging apparatus as claim 2, further comprising a signal processing unit for implementing image processing of signals from said rectangular coil and said butterfly type coil individually.

5. A magnetic resonance imaging apparatus as claim 2, further comprising a signal processing unit for implementing image processing of signals from a pair of quadrature detection coils in such a manner that a combination of signals from said rectangular coil and said butterfly type coil at one side of said object are combined together to produce a combined signal, another combination of signals from said rectangular coil and said butterfly type coil at another side of said object are combined together to produce a combined signal, and the combined signals are processed individually.

6. A magnetic resonance imaging apparatus as claimed in claim 1, wherein each of said quadrature detection coils has a planar shape.

7. A magnetic resonance imaging apparatus as claimed in claim 1, wherein said quadrature detection coils have shapes of curved surfaces.

8. A magnetic resonance imaging apparatus as claimed in claim 7, wherein said quadrature detection coils are bent along a surface shape of the region of interest of said object.

9. A magnetic resonance imaging apparatus as claimed in claim 1, wherein each of said quadrature detection coils, include a rectangular coil and a butterfly type coil in overlapping relation.

10. A magnetic resonance imaging apparatus as claimed in claim 9, wherein said butterfly type coil is made of a conductor forming an 8-shaped coil having two loops coupled together, and an intersecting portion of said two loops contains two conductors extended substantially parallel to each other along said static magnetic field direction.

11. A magnetic resonance imaging apparatus as claim 9, wherein said quadrature detection coils form a detection coil array of a plurality of said quadrature detection coils overlapping one another on opposite sides of the region of interest of said object.

12. A magnetic resonance imaging apparatus as claim 11, further comprising a signal processing unit for implementing image processing of a combined signal obtained by the opposed detection coil arrays.

13. A magnetic resonance imaging apparatus as claim 1, further comprising a signal processing unit for implementing image processing of signals from said quadrature detection coils individually.

14. A magnetic resonance imaging apparatus having a static magnetic field generator disposed on both sides of an object sandwiched therebetween for generating a static magnetic field in a direction perpendicular to a body axis of said object, an RF transmitting coil device for transmitting a radio frequency signal to said object, and an RF receiving coil device for receiving a magnetic resonance object, wherein:

said RF receiving coil device comprises quadrature detection coils for detecting an MR signal rotated on an X-Y plane including an X direction and a Y direction perpendicular to said X direction, and perpendicular to a Z direction of said static magnetic field;

one of said quadrature detection coils being arranged opposite to another of said quadrature detection coils in such a manner that said quadrature detection coils sandwich said static magnetic field and are separated from each other along said X direction;

said quadrature detection coils include a rectangular coil and a butterfly type coil arranged in an overlapping manner within a Z-Y plane including said Z direction and said Y direction;

said rectangular coil is arranged so as to detect the MR signal component along the X direction; and

said butterfly type coil is arranged so as to detect the MR signal along the Y direction.

15. A magnetic resonance imaging apparatus as claimed in claim 14, wherein said butterfly type coil is made of a conductor forming an 8-shaped coil having two loops coupled together, and an intersecting portion of said two loops contains two conductors extended substantially parallel to each other along said static magnetic field direction.

16. A magnetic resonance imaging apparatus comprising a static magnetic field generator disposed on both sides of an object sandwiched therebetween for generating a vertical static magnetic field in a direction perpendicular to a body axis of said object, an RF transmitting coil device for transmitting a radio frequency signal to said object, and an RF receiving coil device for receiving a magnetic resonance signal from said object, wherein said RF receiving coil device comprises a pair of quadrature detection coils including a butterfly type coil arranged so as to detect an MR signal component along a direction of said body axis, one of said pair of quadrature detection coils being arranged to be opposite to another of said pair of quadrature detection coils so that said quadrature detection coils sandwich a region of interest of said object, and said pair of quadrature detection coils being arranged to have an extension direction in parallel with said body axis direction and perpendicular to said static magnetic field direction.

17. A magnetic resonance imaging apparatus as claim 16, wherein said butterfly type coil is made of a conductor forming an 8-shaped coil having two loops coupled together, and an intersecting portion of said two loops contains two conductors extended substantially parallel to each other along said static magnetic field direction.

18. A magnetic resonance imaging apparatus as claim 16, wherein each of said quadrature detection coils has a planar shape.

19. A magnetic resonance imaging apparatus as claim 16, wherein said quadrature detection coils have shapes of curved surfaces.

20. A magnetic resonance imaging apparatus as claim 16, wherein said quadrature detection coils are bent along a surface shape of the region of interest of said object.

21. A magnetic resonance imaging apparatus as claim 16, wherein each of said quadrature detection coils, include said butterfly type coil and a rectangular coil in overlapping relation.

22. A magnetic resonance imaging apparatus as claim 16, further comprising a signal processing unit for implementing image processing of signals from said quadrature detection coils individually.

23. A magnetic resonance imaging apparatus as claim 16, wherein said quadrature detection coils form a detection coil array of a plurality of said quadrature detection coils overlapping one another on opposite sides of the region of interest of said object.

24. A magnetic resonance imaging apparatus as claim 23, further comprising a signal processing unit for implementing image processing of signals obtained by opposed detection coil arrays.