Magnetic resonance imaging apparatus having high frequency coil isolated from gradient coils and a tapered / inclined coil support unit
A magnetic resonance imaging apparatus includes a high-frequency coil and a coil supporting unit. The high frequency coil is disposed inside a gradient coil and that generates a high-frequency magnetic field in a static magnetic field. The coil supporting unit is formed with a substantially cylindrical shape and that supports the high-frequency coil. The coil supporting unit has a certain range including a magnetic field center and formed in parallel with an axial direction. Both ends of the coil supporting unit each have an internal circumference greater than the internal circumference of the certain range.
1. A magnetic resonance imaging (MRI) apparatus comprising:
an MRI gantry including a magnet and gradient magnetic coils disposed about a high-frequency coil and an imaging volume there-within;
said high-frequency coil having a coil pattern with an axial length that is shorter than an axial length of said gradient magnetic coils; and
a coil supporting unit that supports the high-frequency coil with said high-frequency coil being isolated from said gradient magnetic coils, said coil supporting unit having an axial length that is longer than the axial length of said gradient magnetic coils, with said coil supporting unit having a substantially cylindrical shape which tapers radially outward into a larger internal circumference toward at least one axial end thereof; and
the coil supporting unit also being supported by the magnet only at locations that are spaced axially beyond the axial ends of said gradient magnetic coils and having sound insulating material and/or sound absorbing material disposed at only a location between the gradient magnetic coils and tapered portion of the coil supporting unit among locations between the gradient magnetic coils and the coil supporting unit, the location being located right above the tapered portion.
2. The magnetic resonance imaging apparatus according to claim 1 , wherein each of both ends of the coil supporting unit has a thickness that is greater than a thickness of a middle portion thereof.
3. The magnetic resonance imaging apparatus according to claim 1 , wherein external circumferential surfaces extending from respective ends of the coil supporting unit toward a central direction in an axial direction within a certain distance are parallel with an internal circumferential surface of the magnet.
4. The magnetic resonance imaging apparatus according to claim 1 , wherein the coil supporting unit includes parts extending from respective end surfaces toward a central portion thereof, each of the parts having substantially cylindrical shape parallel with an internal circumferential surface of the magnet.
5. The magnetic resonance imaging apparatus according to claim 1 , wherein the coil supporting unit has a substantially cylindrical shape having a perfect-circle cross section or an oval cross section in an xy plane.
6. The magnetic resonance imaging apparatus according to claim 1 , wherein the coil supporting unit is formed of a plurality of fibers and a resin, and has a structure in which the fibers are arranged in a certain direction.
7. The magnetic resonance imaging apparatus according to claim 6 , wherein the fibers at least have a length equal to a round of the internal circumference of a central portion of the coil supporting unit.
8. The magnetic resonance imaging apparatus according to claim 6 , wherein the coil supporting unit includes a hoop winding layer and a helical winding layer.
9. The magnetic resonance imaging apparatus according to claim 8 , wherein the coil supporting unit includes the hoop winding layer at a first layer from an internal circumferential surface thereof.
10. The magnetic resonance imaging apparatus according to claim 6 , wherein the fibers are formed of glass fibers, and
the resin is formed of a polyester resin or an epoxy resin.
11. A magnetic resonance imaging (MRI) apparatus comprising:
an MRI gantry including a magnet and gradient magnetic coils disposed about a high-frequency coil and an imaging volume there-within;
said high-frequency coil having a coil pattern with an axial length that is shorter than an axial length of said gradient magnetic coils; and
a coil supporting unit that supports the high-frequency coil with said high-frequency coil being isolated from said gradient magnetic coils, said coil supporting unit having an axial length that is longer than the axial length of said gradient magnetic coils and cylindrical shape which tapers radially outward into a larger internal circumference toward at least one axial end thereof;
the coil supporting unit being molded by filament winding, and
the coil supporting unit being supported by the magnet only at locations spaced axially beyond axial ends of said gradient magnetic coils and having a sound insulating material and/or a sound absorbing material disposed at only a location between the gradient magnetic coils and a tapered portion of the coil supporting unit among locations between the gradient magnetic coils and the coil supporting unit, the location being located right above the tapered portion.