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US 6,320,383 B1Granted
RF coil, RF magnetic field generating apparatus and magnetic resonance imaging method and apparatus
AssigneeGE Yokogawa Medical Systems, Limited
InventorsYasushi Kato, Tetsuo Ogino, Yukitoshi Shimo
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Abstract
In order to provide a good frequency property and good openness of a magnetic field space, there is provided a quadrature RF coil and RF magnetic field generating apparatus that comprises two RF coils facing each other, each of the RF coils comprising an annular closed loop 602 and a plurality of radial electric paths 604 inside the closed loop 602, and generates an RF magnetic field by quadrature-driving the two RF coils, and a magnetic, resonance imaging method and apparatus employing such an RF magnetic field generating apparatus.
Claims20
A magnetic field generating apparatus comprising:
- a first planar circular coil;
- and
- a second planar circular coil disposed coaxial of and parallel to said first planar circular coil;
- wherein
- said first and second planar circular coils each comprise:
- a first electric path forming an outer annular closed loop;
- a second electric path forming an inner annular closed loop;
- and
- a plurality of third electric paths radially extending from said inner annular closed loop to said outer annular closed loop;
- and wherein
- each of said first electric paths has a pair of terminals for application of RF signals thereto so that said RF signals are split to travel through said plurality of third electric paths and through said second electric path thereby to produce magnetic field by quadrature electric paths without coupling between said first and second planar circular coils.
8 more elements
A magnetic resonance imaging apparatus comprising:
- means for generating a static magnetic field in a Z-direction, wherein three mutually orthogonal directions are defined as an X-direction, a Y-direction, and a Z-direction in a space accommodating a subject under study;
- means for generating a gradient magnetic field in said space;
- means for generating a high frequency magnetic field in said space;
- means for measuring a magnetic resonance signal from said space;
- and
- means for producing an image based on the magnetic resonance signal measured by said means for measuring;
- wherein
- said means for generating a high frequency- magnetic field comprises:
- a first planar circular coil;
- a second planar circular coil disposed coaxial of and parallel to said first planar circular coil;
- wherein
- said first and second planar circular coils each comprises:
- a first electric path forming an outer annular closed loop;
- a second electric path forming an inner annular closed loop;
- and
- a plurality of third electric paths radially extending from said inner annular closed loop to said outer annular closed loop;
- and wherein
- each of said first electric paths has a pair of terminals for application of RF signals thereto so that said RF signals are split to travel through said plurality of third electric paths and through said second electric path thereby to produce magnetic field by quadrature electric paths without coupling between said first and second planar circular coils;
- and
- means for supplying first RF signals, respectively, to a first terminal on said outer annular closed loop of each of said first and second planar circular coils and for supplying second RF signals, which are 90° different in phase from said first RF signals, respectively, to a second terminal on said outer annular closed loop of each of said first and second planar circular coils, said first and second terminals being 90° apart as viewed axially of the first and second planar circular coils.
17 more elements
A magnetic resonance imaging method comprising the steps of:
- generating a static magnetic field in a Z-direction, wherein three mutually orthogonal directions are defined as a Y-direction, an X-direction, and a Z-direction in a space accommodating a subject under study;
- generating a gradient magnetic field in said space;
- generating a high frequency magnetic field in said space;
- measuring a magnetic resonance signal from said space;
- and
- producing an image based on the magnetic resonance signal measured by said measuring step;
- wherein
- said step of generating a high frequency magnetic field is performed using a magnetic field generating apparatus comprising:
- a first planar circular coil;
- a second planar circular coil disposed coaxial of and parallel to said first planar circular coil;
- wherein
- said first and second planar circular coils each comprise:
- a first electric path forming an outer annular closed loop;
- a second electric path forming an inner annular closed loop;
- and
- a plurality of third electric paths radially extending from said inner closed loop to said outer annular closed loop;
- and wherein
- each of said first electric paths has a pair of terminals for application of RF signals thereto so that said RF signal are split to travel through said purality of third electric paths and through said second electric path thereby to produce magnetic field by quadrature electric paths without coupling between said first and second planar circular coils;
- and
- means for supplying first RF signals, respectively, to a first terminal on said outer annular closed loop of each of said first and second planar circular coils and for supply second RF signals, which are 90° different in phase from said first RF signals, respectively, to a second terminal on said outer annular closed loop of each of said first and second planar circular coils, said first and second terminals being 90° apart as viewed axially of the first and second planar circular coils.
17 more elements
Dependencies are inferred from the claim text.