Gradient coil apparatus and method of micro-imaging
First Claim
1. A local gradient coil assembly comprising:
- a first gradient coil arranged to conduct current in opposite directions;
a second gradient coil arranged to conduct current in one direction;
a third gradient coil arranged to conduct current in two planes; and
wherein the first, second, and third gradient coils are positioned about one another to form a single local gradient coil assembly.
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Accused Products
Abstract
A magnetic resonance imaging (MRI) apparatus and method for micro-imaging is provided. The apparatus comprises an MRI system having a gradient coil positioned within a bore of a magnet that impresses a polarizing magnetic field. The apparatus also includes an RF transceiver system, having an RF switch controlled by a pulse module, to transmit RF signals to an RF coil. Upon selection of a micro-imaging scan, a computer activates a micro-imaging gradient coil positioned within the bore of the magnet. The micro-imaging gradient coils are assembled such that, upon energization, substantially linear magnetic field gradients are created along three axes in a localized FOV adjacent to the micro-imaging gradient coils.
29 Citations
32 Claims
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1. A local gradient coil assembly comprising:
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a first gradient coil arranged to conduct current in opposite directions;
a second gradient coil arranged to conduct current in one direction;
a third gradient coil arranged to conduct current in two planes; and
wherein the first, second, and third gradient coils are positioned about one another to form a single local gradient coil assembly. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
wherein the second gradient coil comprises a plurality of loops evenly displaced from one another.
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9. The coil assembly of claim 1 wherein the third gradient coil comprises a plurality of bi-planar coils, each having a plurality of loops and arranged such that current flow in one-half of the bi-planar coils opposes current flow in another one-half of the bi-planar coils.
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10. The coil assembly of claim 1 wherein the first gradient coil is a z-gradient coil, the second coil is a y-gradient coil, and the third coil is an x-gradient coil.
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11. The coil assembly of claim 1 wherein activation of the device causes a micro-imaging scan of a localized region within a micro-FOV.
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12. The coil assembly of claim 1 further comprising:
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an RF coil platform connected to the third gradient coil; and
an RF coil adjacent to the third gradient coil and connected to the RF coil platform.
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13. An MRI apparatus to acquire images comprising:
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a magnetic resonance imaging (MRI) system having a gradient coil positioned within a bore of a magnet that impresses 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 connected to the gradient coil, the gradient coil further comprising;
a first coil aligned along a first axis;
a second coil aligned along the first axis and positioned substantially within the first coil;
a third coil having a plurality of bi-planar coils; and
wherein the first, second, and third coils each provide a different gradient magnetic field. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of acquiring MR data from a localized region comprising the steps of:
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applying a uniform magnetic field to an imaging object;
locating a local gradient coil adjacent to a surface of a localized FOV of the imaging object, such that a plurality of gradients are focused away from the local gradient coil; and
generating a substantially linear gradient over the localized FOV on three axes. - View Dependent Claims (23, 24, 25, 26, 27)
forming a first gradient coil subassembly to produce a dBz/dz gradient;
forming a second gradient coil subassembly to produce a dBz/dy gradient; and
forming a third gradient coil subassembly to produce a dBz/dx gradient.
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24. The method of claim 23 further including the steps of:
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conducting current through the first gradient coil subassembly with orientation in opposite directions;
conducting current through the second gradient coil subassembly with orientation in a common direction; and
conducting current through the third gradient coil subassembly in two planes.
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25. The method of claim 23 wherein the forming of the first, second, and third gradient coil subassemblies includes:
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constructing the first gradient coil subassembly as a first plurality of loops, each capable of conducting current such that current flow is in opposed directions;
constructing the second gradient coil subassembly as a second plurality of loops, each capable of conducting current in a common direction; and
constructing the third gradient coil subassembly as a plurality of bi-planar loops, each capable of conducting current such that current flow in one-half of the bi-planar loops opposes current flow in another one-half of the bi-planar loops.
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26. The method of claim 23 wherein the forming of the first, second, and third gradient coil subassemblies includes:
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forming the first gradient coil subassembly as a first plurality of loops about a z-axis;
forming the second gradient coil subassembly as a second plurality of loops in alignment with the z-axis and positioned substantially within the first gradient coil subassembly; and
forming the third gradient coil subassembly as a set of four bi-planar loops arranged such that a gradient surface is formed by one side of each of the bi-planar loops.
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27. The method of claim 22 wherein the local gradient coil is a surface coil that does not encircle a region of interest to be scanned.
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28. A micro-imaging gradient coil comprising:
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means for creating a dBz/dz gradient on a localized FOV;
means for creating a dBz/dy gradient on the localized FOV;
means for creating a dBz/dx gradient on the localized FOV; and
means for locating the micro-imaging gradient coil adjacent to a surface of the localized FOV of the imaging object, such that the localized FOV is positioned in a region external to the micro-imaging gradient coil. - View Dependent Claims (29, 30, 31, 32)
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Specification