Surface coils with integrated shims
First Claim
1. A method of localized shimming of a main magnetic field in magnetic resonance imaging comprising:
- (a) generating a localized magnetic field that is substantially equal and opposite to localized non-uniformities in a main magnetic field of a magnetic resonance imaging apparatus, said non-uniformities resulting from the geometric shape and susceptibility of a localized region of a subject being imaged within the main magnetic field.
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Accused Products
Abstract
A localized shim coil (34) for use in a magnetic resonance imaging system includes a plurality of conductive elements (22a-d). The plurality of conductive elements (62a-d) are connected to a current source (64). The plurality of conductive elements (62a-d) are arranged adjacent to a localized region of a subject being imaged such that current flowing through the conductive elements generates a localized magnetic field. A plurality of series connected choke and resister pairs (66a-d) and (68a-d), respectively, are connected to the plurality of conductive elements (62a-d). The chokes (66a-d) present high impedance to currents having frequencies substantially the same as a resonant frequency of the magnetic resonance imaging system. The resisters (68a-d) balance the current flowing through each conductive element (62a-d). The localized magnetic field is generated such that it is substantially equal and opposite to localized non-uniformities generated in the magnetic resonance system'"'"'s main magnetic field by the subject'"'"'s geometric shape and magnetic susceptibility in the localized region being imaged.
18 Citations
17 Claims
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1. A method of localized shimming of a main magnetic field in magnetic resonance imaging comprising:
(a) generating a localized magnetic field that is substantially equal and opposite to localized non-uniformities in a main magnetic field of a magnetic resonance imaging apparatus, said non-uniformities resulting from the geometric shape and susceptibility of a localized region of a subject being imaged within the main magnetic field. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of magnetic resonance imaging including generating a temporally constant magnetic field through a region of interest of a subject, in the region of interest, the temporally constant magnetic field has an inhomogeneity, exciting resonance in the region of interest, receiving induced resonance signals, and reconstructing a magnetic resonance image from the received resonance signal, the method further comprising:
temporarily generating a correction magnetic field in the region of interest contemporaneously with the exciting of magnetic resonance, to correct the inhomogeneity. - View Dependent Claims (8, 9, 10, 11)
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12. A method of imaging a subject'"'"'s anatomy, said method comprising:
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(a) generating a temporally constant main magnetic field; (b) positioning the subject'"'"'s anatomy within the main magnetic field, said subject'"'"'s anatomy introducing localized non-uniformities in the main magnetic field; (c) producing, in a vicinity of the subject'"'"'s anatomy, a localized corrective magnetic field, said localized corrective magnetic field being substantially equal to and opposite of the localized non-uniformities in the main magnetic field; (d) inducing magnetic resonance in dipoles within the subject'"'"'s anatomy; (e) receiving signals from the resonating dipoles; and
,(f) reconstructing an image representation of the subject'"'"'s anatomy from the received signals. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification