Degenerate birdcage coil and transmit/receive apparatus and method for same
First Claim
1. A birdcage coil system for use in conjunction with a magnetic resonance apparatus, the birdcage coil system comprising:
- a birdcage coil tuned to degeneracy the coil including;
a first conductive loop,a second conductive loop, anda plurality of first conductor rungs disposed between the first and second conductive loops and in electrical connection therewith; and
a switching system which switches the birdcage coil at least between;
an RF transmit mode, andan RF receive mode,the switching system including;
a plurality of RF transmit feed points in electrical connection with the first conductive loop for feeding RF transmit signals to the coil;
a plurality of transmit PIN diodes for coupling RF transmit feeds to the feed points;
a plurality of RF receive take-off points disposed across matching capacitors;
a plurality of matching PIN diodes arranged in parallel with the matching capacitors; and
a plurality of cage DC bias inputs in electrical connection with the transmit and matching diodes for biasing the transmit and matching PIN diodes.
1 Assignment
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Accused Products
Abstract
A birdcage coil (16) used in conjunction with a magnetic resonance imaging apparatus includes a first conductive loop (81, 581), a second conductive loop (82, 582), and a plurality of first conductor rungs (80, 580) disposed between the first and second conductive loops. A third conductor (83, 83″, 583) is coupled to the second conductive loop at resonance frequencies, such as by second conductor rungs (84, 84″, 584). The birdcage coil also includes switches (590) for switching the birdcage coil at least among: 1) an RF transmit mode to operate as an RF transmit coil; and 2) an RF receive mode to operate as an RF receive coil.
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Citations
26 Claims
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1. A birdcage coil system for use in conjunction with a magnetic resonance apparatus, the birdcage coil system comprising:
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a birdcage coil tuned to degeneracy the coil including; a first conductive loop, a second conductive loop, and a plurality of first conductor rungs disposed between the first and second conductive loops and in electrical connection therewith; and a switching system which switches the birdcage coil at least between; an RF transmit mode, and an RF receive mode, the switching system including; a plurality of RF transmit feed points in electrical connection with the first conductive loop for feeding RF transmit signals to the coil; a plurality of transmit PIN diodes for coupling RF transmit feeds to the feed points; a plurality of RF receive take-off points disposed across matching capacitors; a plurality of matching PIN diodes arranged in parallel with the matching capacitors; and a plurality of cage DC bias inputs in electrical connection with the transmit and matching diodes for biasing the transmit and matching PIN diodes. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A birdcage coil system for use in conjunction with a magnetic resonance apparatus, the birdcage coil system comprising:
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a birdcage coil tuned to degeneracy, the coil including; first conductive loop, a second conductive loop, and a plurality of first conductor rungs disposed between the first and second conductive loops and in electrical connection therewith; and switching elements switch the birdcage coil at least between; an RF transmit mode, and an RF receive mode, a plurality of feed points on the first conductive loop, for feeding RF transmit signals to the coil, the switching means elements further including; a plurality of preamp PIN diodes in electrical connection with corresponding RF receive pre-amplifiers, the receive pre-amplifiers being connected with take-off points on one of the conductive loops; a plurality of preamp DC bias inputs in electrical connection with the preamp PIN diodes for biasing the preamp diodes and shorting-out the RF receive pre-amplifiers. - View Dependent Claims (8)
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9. A birdcage coil system for use in conjunction with a magnetic resonance imaging apparatus, the birdcage coil system comprising:
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a birdcage coil tuned to degeneracy, the coil including; a first conductive loop, a second conductive loop, a plurality of first conductor rungs disposed between the first and second conductive loops and in electrical connection therewith, a third conductor coupled at radio frequencies with the second conductive loop; a plurality of second conductor rungs disposed between the second conductive loop and third conductor and in electrical connection therewith, wherein reactances of at least one of the third conductor and the plurality of second conductor rungs are selected to decouple next-neighbor meshes of the birdcage coil; and a switching means for switching the birdcage coil at least between; an RF transmit mode, and an RF receive mode in which in the birdcage coil is adapted to operate as a phased array RF receive coil. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A birdcage coil system for use in conjunction with a magnetic resonance imaging apparatus, the birdcage coil system comprising:
a birdcage coil tuned to degeneracy, the coil including; a first conductive loop, the first conductive loop being interrupted by a plurality of matching capacitors, a second conductor loop, a plurality of first conductor rungs disposed between the first and second conductive loops and in electrical connection therewith, a third conductive loop capacitively coupled to the second conductive loop, a plurality of second conductor rungs disposed between the second and third conductive loops and in electrical connection therewith, a plurality of feed points for feeding RF transmit signals to the coil from an RF transmitter in a transmit mode, a plurality of take-off points defined across the matching capacitors from which received signals are conveyed to a plurality of preamplifiers in a receive mode, and wherein reactances of at least one of third conductive loop and the plurality of second conductor rungs are selected to decouple next-neighbor meshes of the birdcage coil. - View Dependent Claims (26)
Specification