Self-shielded coil with non-inductive winding

A self-shielded magnetic gradient coil unit for magnetic resonance imaging producing three mutually orthogonal X-, Y-, and Z-axes directions of magnetic gradients, the unit comprising:

• an X-channel gradient coil assembly for providing a gradient in the X-axis direction;
• a Y-channel gradient coil assembly for providing a gradient in the Y-axis direction;
• and
• a Z-channel gradient coil assembly for providing a gradient in the Z-axis direction,
• each of the X-, Y- and Z-channel gradient coil assemblies having a main coil and a shield coil, the main coil of each channel having a first patterned winding formed by a first conductive wire wound on a predetermined main coil pattern, and a shield coil having a second patterned winding formed by a second conductive wire wound on a further predetermined shield coil pattern to reduce leakage from the unit of gradient field provided by the main coil;
• and
• at least one of the first and second conductive wires being divided over substantially its entire length into a plurality of branch wires wound into a divided-turn structure having a non-inductive winding configuration with respect to magnetic flux passing through a closed loop formed by the branch wires.

An MRI (magnetic resonance imaging) system having a self-shielded gradient coil unit producing three mutually orthogonal X-, Y-, and Z-axes directions of magnetic gradients, the system comprising:

• a static magnetic field generator,
• an RF coil;
• MRI signal acquisition and processor circuit s connected to MRI signals;
• an X-channel gradient coil assembly for providing a gradient in the X-axis direction;
• a Y-channel gradient coil assembly for providing a gradient in the Y-axis direction;
• and
• a Z-channel gradient coil assembly for providing a gradient in the Z-axis direction,
• each of the X-, Y- and Z-channel gradient coil assemblies having a main coil and a shield coil, the main coil having a first patterned winding formed by a first conductive wire wound on a predetermined main coil pattern, and the shield coil having a second patterned winding formed by a second conductive wire wound on a further predetermined shield coil pattern to reduce leakage from the gradient coil assemblies of gradient field provided by the main coil;
• and
• at least one of the first and second conductive wires being divided, over substantially its entire length into a plurality of branch wires wound into a divided-turn structure having a non-inductive winding configuration with respect to magnetic flux passing through a closed loop formed by the branch wires.