COIL UNIT AND MAGNETIC RESONANCE IMAGING APPARATUS INCLUDING COIL UNIT
A coil unit can be configured for a reception coil to avoid interference between high-frequency circuits included in the reception coil and coupling with a transmission coil and to suppress an influence of the transmission coil on the high-frequency circuit of the reception coil. A coil unit of an MRI apparatus includes a plurality of coil elements arranged in a two-dimensional direction, a wiring line connected to each coil element and configured to bundle a signal line, and baluns provided at a plurality of positions of the wiring line, in which at least a part of the wiring line runs from one end toward other end in an arrangement direction of the coil elements while being folded back in a direction oblique to the arrangement direction.
1 . A coil unit of an MRI apparatus, comprising:
a plurality of coil elements arranged in a two-dimensional direction,
a wiring line connected to each coil element and configured to transmit a signal or electricity; and
baluns provided at a plurality of positions of the wiring line,
wherein at least a part of the wiring line runs from one end toward the other end in an arrangement direction of the coil elements while being folded back in a direction oblique to the arrangement direction.
2 . The coil unit according to claim 1 ,
wherein at least a part of the baluns is disposed at a folding-back point of the wiring line.
3 . The coil unit according to claim 1 ,
wherein at least a part of the baluns is disposed between a folding-back point and a next folding-back point of the wiring line.
4 . The coil unit according to claim 1 ,
wherein at least one balun is disposed on a wiring line between one folding-back point and a next folding-back point.
5 . The coil unit according to claim 1 , further comprising:
a connecting part configured to connect the wiring line to a cable of an MRI apparatus,
wherein the connecting part is provided at an end part of an arrangement of the coil elements in a longitudinal direction.
6 . The coil unit according to claim 1 , further comprising:
a connecting part configured to connect the wiring line to a cable of an MRI apparatus,
wherein the connecting part is provided at an end part of an arrangement of the coil elements in a lateral direction.
7 . The coil unit according to claim 1 ,
wherein a length of the wiring line to one folding-back point and a length of the wiring line to the other folding-back point are different from each other with the balun interposed therebetween.
8 . The coil unit according to claim 1 ,
wherein a distance between adjacent folding-back points of the wiring line is 1/16 or less of a wavelength of a high-frequency signal transmitted and received by an MRI apparatus.
9 . The coil unit according to claim 1 ,
wherein the balun is a parallel resonance circuit, and a resonance frequency is f 0 ±10% in a case where a reference frequency of an MRI apparatus is denoted by f 0 .
10 . The coil unit according to claim 1 ,
wherein the balun includes a balun composed of a solenoid coil or a figure-eight-shaped coil formed of a shield line of the wiring line and a capacitor connected in parallel to both ends of the solenoid coil or the figure-eight-shaped coil.
11 . The coil unit according to claim 10 ,
wherein the balun includes a balun composed of a solenoid coil or a figure-eight-shaped coil formed of the wiring line connected to the coil elements and a capacitor connected in parallel to both ends of the solenoid coil or the figure-eight-shaped coil.
12 . The coil unit according to claim 1 ,
wherein the balun is an LC circuit connected in series to the wiring line.
13 . The coil unit according to claim 1 ,
wherein the balun is a clamp-type balun mounted on an outer periphery of the wiring line.
14 . The coil unit according to claim 13 ,
wherein the clamp-type balun is mounted at a mounting position in the wiring line to include a plurality of the wiring lines connected to the coil elements.
15 . A magnetic resonance imaging apparatus comprising:
an RF transmission coil configured to generate a high-frequency magnetic field in an imaging space in which a static magnetic field is formed; and
an RF reception coil configured to receive a nuclear magnetic resonance signal generated from a subject placed on the imaging space,
wherein the RF reception coil includes the coil unit according to claim 1 .