Gradient coil apparatus and methods for MRI

1. A coil apparatus for magnetic resonance imaging, comprising:

at least one wire winding, the at least one wire winding comprising at least one hollow cross-section wire and at least one solid cross-section wire,

the at least one solid cross-section wire comprising at least one solid small cross-section wire and at least one solid large cross-section wire,

the at least one solid large cross-section wire having a cross-section area greater than that of the at least one solid small cross-section wire,

the at least one solid small cross-section wire disposed in one of adjacent and proximate at least one of the at least one hollow cross-section wire and the at least one solid large cross-section wire, and

the at least one solid cross-section wire disposed at a radial position distinct from a radial position of the at least one hollow cross-section wire,

whereby at least one of current density, winding density, and heat extraction are increasable.

2. The apparatus of claim 1 ,

wherein the at least one wire winding comprises at least one portion,

wherein a portion comprises at least one of the at least one hollow cross-section wire and the at least one solid small cross-section wire,

wherein another portion comprises at least one of the at least one hollow cross-section wire being spaced apart and the at least one solid small cross-section wire being spaced apart, and

wherein the at least one wire winding is configured as one of a Z-gradient coil, a uniform field coil, and a B 0 offset coil.

3. The apparatus of claim 1 , wherein the at least one solid cross-section wire comprises a width less than that of the at least one hollow cross-section wire.

4. The apparatus of claim 1 , wherein each at least one solid cross-section wire is disposed in one of adjacent and proximate two hollow cross-section wires.

5. The apparatus of claim 1 , wherein a plurality of solid cross-section wires are disposed in one of adjacent and proximate each at least one hollow cross-section wire.

6. The apparatus of claim 1 ,

wherein the at least one wire winding is configured as a Z-gradient coil,

wherein the at least one solid cross-section wire comprises a cross-sectional area less than that of the at least one hollow cross-section wire,

wherein one of:

each at least one solid cross-section wire is disposed in one of adjacent and proximate two hollow cross-section wires, and

two solid cross-section wires are disposed in one of adjacent and proximate each at least one hollow cross-section wire.

7. The apparatus of claim 1 ,

wherein the at least one hollow cross-section wire comprises a plurality of hollow cross-section wires,

wherein the plurality of hollow cross-section wires comprises a set of hollow cross-section wires,

wherein each hollow cross-section wire of the set comprises a plurality of parallel manifolds for increasing total coolant flow rate, for a given pressure drop across the set, wherein heat extraction is increasable,

wherein the plurality of parallel manifolds facilitates electrical current flow from one set to one of an adjacent set and a proximate set,

wherein the plurality of parallel manifolds directs coolant flow in relation to a winding segment, and

wherein each parallel manifold of the plurality of parallel manifolds is configured to insert into each at least one hollow cross-section wire via a through-hole and to effect parallel coolant flow paths to reduce overall flow resistance and to improve cooling.

8. The apparatus of claim 1 , further comprising an electrically insulating thermally transferring layer disposed in at least one of: between at least a portion of the at least one solid cross-section wire and at least a portion of the at least one hollow cross-section wire, on at least a portion of the at least one solid cross-section wire, and on at least a portion of the at least one hollow cross-section wire,

wherein the electrically insulating thermally transferring layer facilitates electrical separation between the at least one hollow wire and the at least one solid cross-section wire, and

wherein the electrically insulating thermally transferring layer facilities heat transfer, and

wherein the electrically insulating thermally transferring layer comprises at least one of a polyimide film, an enamel coating, a thermally conductive enamel coating, an epoxy layer, a thermally conductive epoxy layer, and any other suitable electrically insulating material,

whereby heat transfer for cooling apparatus is facilitated.

9. A method of fabricating a coil apparatus for magnetic resonance imaging, comprising:

providing at least one wire winding, providing the at least one wire winding comprising providing at least one hollow cross-section wire and at least one solid cross-section wire,

providing the at least one solid cross-section wire comprising providing at least one solid small cross-section wire and at least one solid large cross-section wire,

providing the at least one solid large cross-section wire comprising providing the at least one solid large cross-section wire having a cross-sectional area greater than that of the at least one solid small cross-section wire,

providing the at least one solid small cross-section wire comprising disposing the at least one solid small cross-section wire in one of adjacent and proximate at least one of the at least one hollow cross-section wire and the at least one solid large cross-section wire, and

providing the at least one solid cross-section wire comprising disposing the at least one solid cross-section wire at a radial position distinct from a radial position of the at least one hollow cross-section wire,

whereby at least one of current density, winding density, and heat extraction are increasable.

10. The method of claim 9 ,

wherein providing the at least one wire winding comprises providing at least one portion, providing at least one portion comprising providing a portion and providing another portion,

wherein providing a portion comprises providing at least one of the at least one hollow cross-section wire and the at least one solid small cross-section wire,

wherein providing another portion comprises providing at least one of the at least one hollow cross-section wire being spaced apart and the at least one solid small cross-section wire being spaced apart, and

wherein providing the at least one wire winding comprises configuring the at least one wire winding one of a Z-gradient coil, a uniform field coil, and a B 0 offset coil.

11. The method of claim 9 , wherein providing the at least one solid cross-section wire comprises providing the at least one solid cross-section wire with a width less than that of the at least one hollow cross-section wire.

12. The method of claim 9 , wherein providing the at least one solid cross-section wire comprises disposing each at least one solid cross-section wire in one of adjacent and proximate two hollow cross-section wires.

13. The method of claim 9 , wherein providing the at least one solid cross-section wire comprises disposing a plurality of solid cross-section wires in one of adjacent and proximate each at least one hollow cross-section wire.

14. The method of claim 9 ,

wherein providing the at least one wire winding comprises configuring the at least one wire winding as a Z-gradient coil;

wherein providing the at least one solid cross-section wire comprises providing the at least one solid cross-section wire with a cross-sectional area less than that of the at least one hollow cross-section wire,

wherein of one:

providing the at least one solid cross-section wire comprises disposing each at least one solid cross-section wire in one of adjacent and proximate two hollow cross-section wires,

providing the at least one solid cross-section wire comprises disposing two solid cross-section wires in one of adjacent and proximate each at least one hollow cross-section wire.

15. A method of increasing at least one of current density, winding density, and heat extraction for magnetic resonance imaging by way of a coil apparatus, comprising:

providing the coil apparatus, providing the apparatus comprising providing at least one wire winding, providing the at least one wire winding comprising providing at least one hollow cross-section wire and at least one solid cross-section wire, providing the at least one solid cross-section wire comprising providing at least one solid small cross-section wire and at least one solid large cross-section wire, providing the at least one large cross-section wire comprising providing the at least one large cross-section wire having a cross-sectional area greater than that of the at least one small cross-section wire, providing the at least one solid small cross-section wire disposed in one of adjacent and proximate at least one of the at least one hollow cross-section wire and the at least one solid large cross-section wire, and providing the at least one solid cross-section wire comprising disposing the at least one solid cross-section wire at a radial position distinct from a radial position of the at least one hollow cross-section wire, whereby at least one of current density, winding density, and heat extraction are increasable; and

applying a current through the gradient coil apparatus,

thereby increasing at least one of current density, winding density, and heat extraction.

16. The method of claim 15 ,

wherein providing the at least one wire winding comprises providing at least one portion, providing at least one portion comprising providing a portion and providing another portion,

wherein providing a portion comprises providing at least one of the at least one hollow cross-section wire and the at least one solid small cross-section wire,

wherein providing another portion comprises providing at least one of the at least one hollow cross-section wire being spaced apart and the at least one solid small cross-section wire being spaced apart, and

wherein providing the at least one wire winding comprises configuring the at least one wire winding as one of a Z-gradient coil, a uniform field coil, and a B 0 offset coil.

17. The method of claim 15 , wherein providing the at least one solid cross-section wire comprises providing the at least one solid cross-section wire with a cross-sectional area less than that of the at least one hollow cross-section wire.

18. The method of claim 15 , wherein providing the at least one solid cross-section wire comprises disposing each at least one solid cross-section wire in one of adjacent and proximate two hollow cross-section wires.

19. The method of claim 15 , wherein providing the at least one solid cross-section wire comprises disposing a plurality of solid cross-section wires in one of adjacent and proximate each at least one hollow cross-section wire.

20. The method of claim 15 ,

wherein providing the at least one wire winding comprises configuring the at least one wire winding as a Z-gradient coil;

wherein providing the at least one solid cross-section wire comprises providing the at least one solid cross-section wire with a cross-sectional area less than that of the at least one hollow cross-section wire,

wherein of one:

providing the at least one solid cross-section wire comprises disposing each at least one solid cross-section wire in one of adjacent and proximate a plurality of hollow cross-section wires,

providing the at least one solid cross-section wire comprises disposing a plurality of solid cross-section wires in one of adjacent and proximate each at least one hollow cross-section wire.