US4918388A — Quadrature surface coils for magnetic resonance i…

Claim 1

Independent Claim 104 words

A magnetic resonance imaging apparatus comprising: a main magnetic field means for providing a magnetic field through an examination region; a magnetic resonance excitation means for exciting magnetic resonance of nuclei of a subject in the examination region; a thin quadrature coil for quadrature detecting magnetic resonance signals from the excited nuclei of the subject including: a thin dielectric layer; a thin loop coil fixedly mounted on one surface of the thin dielectric layer; a thin Helmholtz coil fixedly mounted on an obverse surface of the thin dielectric layer; and, processing means for processing the quadrature detected magnetic resonance signals into an image representation.

Claim 2

Dependent Claim 104 words

A magnetic resonance imaging apparatus comprising: a main magnetic field means for providing a magnetic field through an examination region; a magnetic resonance excitation means for exciting magnetic resonance of nuclei of a subject in the examination region; a thin quadrature coil for quadrature detecting magnetic resonance signals from the excited nuclei of the subject including: a thin dielectric layer; a thin loop coil fixedly mounted on one surface of the thin dielectric layer; a thin Helmholtz coil fixedly mounted on an obverse surface of the thin dielectric layer; and, processing means for processing the quadrature detected magnetic resonance signals into an image representation.

Claim 3

Dependent Claim 54 words

The apparatus as set forth in claim 1 wherein the loop coil has an associated magnetic field along a first axis; and, the Helmholtz coil has an associated magnetic field along a second axis, the loop and Helmholtz coils being disposed along generally parallel surfaces and the first and second axes being generally orthogonal.

Claim 4

Dependent Claim 24 words

The apparatus as set forth in claim 1 wherein the thin dielectric layer is curved to conform to a surface portion of the subject.

Claim 5

Dependent Claim 22 words

The apparatus as set forth in claim 2 wherein the loop and Helmholtz coils are symmetric about a common axis of symmetry.

Claim 6

Dependent Claim 90 words

A magnetic resonance imaging apparatus comprising: a main magnetic field means for providing a magnetic field through an examination region; a magnetic resonance excitation means for exciting magnetic resonance of nuclei of a subject in the examination region; first and second coils lying on parallel surfaces for quadrature detecting magnetic resonance signals from the excited nuclei of the subject, the first coil being a loop coil and the second coil being a Helmholtz; pair coil; and, processing means for processing the quadrature detected magnetic resonance signals into an image representation.

Claim 7

Dependent Claim 90 words

A magnetic resonance imaging apparatus comprising: a main magnetic field means for providing a magnetic field through an examination region; a magnetic resonance excitation means for exciting magnetic resonance of nuclei of a subject in the examination region; first and second coils lying on parallel surfaces for quadrature detecting magnetic resonance signals from the excited nuclei of the subject, the first coil being a loop coil and the second coil being a Helmholtz; pair coil; and, processing means for processing the quadrature detected magnetic resonance signals into an image representation.

Claim 8

Dependent Claim 84 words

A flat coil assembly for quadrature detecting magnetic resonance signals, the coil assembly comprising: a first, coil disposed along a first plane with its associated magnetic field generally transverse to the first plane; and, a Helmholtz coil disposed along a second plane, the first and second planes being disposed parallel and contiguous to each other, the Helmholtz coil having an associated magnetic field that lies substantially orthogonal to the first magnetic fields, such that the first and second coils quadrature detect magnetic resonance signals.

Claim 9

Dependent Claim 84 words

A flat coil assembly for quadrature detecting magnetic resonance signals, the coil assembly comprising: a first, coil disposed along a first plane with its associated magnetic field generally transverse to the first plane; and, a Helmholtz coil disposed along a second plane, the first and second planes being disposed parallel and contiguous to each other, the Helmholtz coil having an associated magnetic field that lies substantially orthogonal to the first magnetic fields, such that the first and second coils quadrature detect magnetic resonance signals.

Claim 10

Dependent Claim 31 words

The coil assembly as set forth in claim 6 wherein the first and second coils are symmetric about a plane of symmetry which is perpendicular to the first and second planes.

Claim 11

Dependent Claim 17 words

The coil assembly as set forth in claim 7 wherein the first coil is a loop coil.

Claim 12

Dependent Claim 66 words

A quadrature coil assembly comprising: a dielectric sheet; a first coil having an associated magnetic field along a first axis, the first coil being mounted to the dielectric sheet; and, a Helmholtz coil having an associated magnetic filed along a second axis, the second coil being mounted to the dielectric sheet and the second axis being substantially orthogonal to the first axis for quadrature coil operation.

Claim 13

Dependent Claim 66 words

A quadrature coil assembly comprising: a dielectric sheet; a first coil having an associated magnetic field along a first axis, the first coil being mounted to the dielectric sheet; and, a Helmholtz coil having an associated magnetic filed along a second axis, the second coil being mounted to the dielectric sheet and the second axis being substantially orthogonal to the first axis for quadrature coil operation.

Claim 14

Dependent Claim 26 words

The coil assembly as set forth in claim 9 wherein the dielectric sheet is curved to conform to a surface portion of an object being examined.

Claim 15

Dependent Claim 24 words

The coil assembly as set forth in claim 9 wherein the first and Helmholtz coils are mounted to opposite faces of the dielectric sheet.

Claim 16

Dependent Claim 20 words

The coil assembly as set forth in claim 11 wherein the first and Helmholtz coils are constructed of thin foil.

Claim 17

Dependent Claim 111 words

A coil assembly comprising: a first coil having an associated magnetic field along a first axis; a second coil having an associated magnetic field along a second axis, the first and second coils being mounted closely adjacent and such that the first and second axes are substantially orthogonal; a phase shift circuit operatively connected with one of the first and second coils for phase shifting received signals by 90°; a combining means for combining the phase shifted signal from one coil with the signal from the other coil; a cable for connecting the combining means with a radio frequency receiver; and, a matching means for matching the impedance of the cable.

Claim 18

Dependent Claim 111 words

A coil assembly comprising: a first coil having an associated magnetic field along a first axis; a second coil having an associated magnetic field along a second axis, the first and second coils being mounted closely adjacent and such that the first and second axes are substantially orthogonal; a phase shift circuit operatively connected with one of the first and second coils for phase shifting received signals by 90°; a combining means for combining the phase shifted signal from one coil with the signal from the other coil; a cable for connecting the combining means with a radio frequency receiver; and, a matching means for matching the impedance of the cable.

Claim 19

Dependent Claim 118 words

A coil assembly comprising: a first coil associated with a magnetic field along a first axis; a second coil associated with a magnetic field along a second axis, the first and second coils being tuned to a preselected magnetic resonance frequency the first and second coils being mounted closely adjacent and such that the first and second axes are substantially orthogonal; a decoupling means for selectively detuning the first and second coils from the preselected magnetic resonance frequency a phase shift circuit operatively connected with one of the first and second coils for phase shifting received signals by 90°; and, a combining mean for combining the phase shifted signal from one coil with the signal from other coil.

Claim 20

Dependent Claim 118 words

A coil assembly comprising: a first coil associated with a magnetic field along a first axis; a second coil associated with a magnetic field along a second axis, the first and second coils being tuned to a preselected magnetic resonance frequency the first and second coils being mounted closely adjacent and such that the first and second axes are substantially orthogonal; a decoupling means for selectively detuning the first and second coils from the preselected magnetic resonance frequency a phase shift circuit operatively connected with one of the first and second coils for phase shifting received signals by 90°; and, a combining mean for combining the phase shifted signal from one coil with the signal from other coil.

Claim 21

Dependent Claim 127 words

A coil assembly comprising: a first coil associated with a magnetic field along a first axis; a second coil associated with a magnetic field along a second axis, the first and second coils being mounted closely adjacent and such that the first and second axes are substantially orthogonal; a first phase shifting circuit associated with the first coil for phase shifting received signals by 90°; a second 90° phase shifting circuit associated with the second coil; a combining means for combining the phase shifted signal from one coil with the signal from the other coil; and, a switching means for selectively switching one of the 90° phase shift circuits between its associated coil and the combining means for connecting the other coil directly with the combining means.

Claim 22

Dependent Claim 127 words

A coil assembly comprising: a first coil associated with a magnetic field along a first axis; a second coil associated with a magnetic field along a second axis, the first and second coils being mounted closely adjacent and such that the first and second axes are substantially orthogonal; a first phase shifting circuit associated with the first coil for phase shifting received signals by 90°; a second 90° phase shifting circuit associated with the second coil; a combining means for combining the phase shifted signal from one coil with the signal from the other coil; and, a switching means for selectively switching one of the 90° phase shift circuits between its associated coil and the combining means for connecting the other coil directly with the combining means.

Claim 23

Dependent Claim 108 words

A coil assembly comprising: a first coil associated with a magnetic field along a first axis; a second coil extending in generally a semi-ellipse and associated with a magnetic field along a second axis, the first and second coils being mounted closely adjacent and such that the first and second axes are substantially orthogonal, whereby the coil assembly is contoured generally in accordance with a patient's neck; a phase shift circuit operatively connected with one of the first and second coils for phase shifting received signals by 90°; and, a combining means for combining the phase shifted signal from one coil with the signal from the other coil.

Claim 24

Dependent Claim 108 words

A coil assembly comprising: a first coil associated with a magnetic field along a first axis; a second coil extending in generally a semi-ellipse and associated with a magnetic field along a second axis, the first and second coils being mounted closely adjacent and such that the first and second axes are substantially orthogonal, whereby the coil assembly is contoured generally in accordance with a patient's neck; a phase shift circuit operatively connected with one of the first and second coils for phase shifting received signals by 90°; and, a combining means for combining the phase shifted signal from one coil with the signal from the other coil.

Claim 25

Dependent Claim 108 words

A coil assembly comprising: a first coil associated with a magnetic field along a first axis; a second coil associated with a magnetic field along a second axis, the second coil includes two coil portions which are disposed at generally at 45° angle relative to each other, the first and second coils being mounted closely adjacent and such that the first and second axes are substantially orthogonal; a phase shift circuit operatively connected with one of the first and second coils for phase shifting received signals by 90°; and, a combining means for combining the phase shifted signal from one coil with the signal from the other coil.

Claim 26

Dependent Claim 108 words

A coil assembly comprising: a first coil associated with a magnetic field along a first axis; a second coil associated with a magnetic field along a second axis, the second coil includes two coil portions which are disposed at generally at 45° angle relative to each other, the first and second coils being mounted closely adjacent and such that the first and second axes are substantially orthogonal; a phase shift circuit operatively connected with one of the first and second coils for phase shifting received signals by 90°; and, a combining means for combining the phase shifted signal from one coil with the signal from the other coil.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-04-16	1993-10-16	1994-04-17	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-04-16	1997-10-16	1998-04-17	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-04-16	2001-10-16	2002-04-17	$7700.00	Window Closed / Lapsed

Quadrature surface coils for magnetic resonance imaging

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag