Gradient coil set capable of producing a variable field of view
AssigneeGE Medical Systems Global Technology Company, LLC
InventorQin Liu
Life of this patent
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Abstract
The present invention is directed to a coil assembly capable of producing a flexible FOV for use with an MRI system. The coil assembly includes a gradient coil disposed about an imaging axis and a plurality of higher order gradient coils, or shim coils, positioned about the primary gradient coil such that the plurality of higher gradient order coils have a radius greater than the radius of the primary gradient coil. A change in the FOV is realized by modulating the current in the higher order gradient coils or shim coils.
Claims25
A coil assembly with variable FOV for use with an MR imaging system, the coil assembly comprising:
- a gradient coil disposed about an imaging axis to produce a gradient field, the gradient coil having a first end and a second end;
- a first portion of a higher order gradient coil positioned overlapping at least a portion of the first end of the gradient coil;
- and
- a second portion of the higher order gradient coil positioned overlapping at least a portion of the second end of the gradient coil.
An MRI system comprising:
- a magnetic resonance imaging (MRI) system has a gradient coil positioned about a bore of a magnet to produce a polarizing magnetic field and an RF transceiver system and an RF switch controlled by a pulse module to transmit RF signals to an RF coil assembly to acquire MR images of a field-of-view (FOV);
- at least one independent higher order gradient coil configured to adjust gradient field linearity and generally disposed about an imaging axis;
- and
- a control to vary the FOV by modulating current in the at least one higher order gradient coil based on a reception of instructions.
The MRI system of 7 wherein the at least one higher order gradient coil and the plurality of gradient coils are arranged in series and the control provides a larger FOV or a smaller FOV than an FOV associated with the gradient coil alone based on an operator input.
A method of manufacturing a coil assembly for an MR imaging apparatus, the method comprising the steps of:
- positioning a primary gradient coil about a bore of a magnet, the primary gradient coil having a first and a second end;
- positioning a first portion of a higher order gradient coil circumferentially about the first end such that the portion overlaps at least a portion of the first end;
- and
- positioning a second portion of a higher order gradient coil circumferentially about the second end such that the second portion overlaps at least a portion of the second end.
A method of producing a variable FOV with an MR system having a gradient coil to produce a gradient field and an independent higher order gradient coil, the method comprising the steps of:
- energizing the gradient coils and the independent higher order gradient coil with a current to produce a gradient field of magnetic field gradients to spatially encode acquired signals in an FOV;
- and
- modulating the current in the independent higher order gradient coil to vary the FOV.
Dependencies are inferred from the claim text.