US5386191A
Expired / Lapsed
US
⏱️ 0.0 years remaining
RF coil providing reduced obstruction access to image volume in transverse magnet MRI system
Assignee: University of California
•
Filing: 1993-03-01
•
Granted: 1995-01-31
•
Expires: 2013-03-01
Abstract
Abstract An RF coil sub-assembly for a transverse magnet MRI system includes substantially co-planar serially-connected turns mounted on a common substrate. Preferably, half of the turns are directed clockwise, while the other half are directed counter clockwise to produce a plurality of equal commonly directed currents along spaced apart parallel conductors. A low-loss expanded dielectric spacer is used to mount the RF coils within a pre-existing depression formed by the annular magnetic shims of a transverse magnet structure thus substantially eliminating any obstruction to the image volume for at least the RF transmit coils.
Inventors
- 👤 Barry McCarten
- 👤 Joseph W. Carlson
- 👤 Mitsuaki Arakawa
- 👤 Leon Kaufman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:28
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/34; G01R33/341; G01R33/36; G01R33/3628; G01R33/34007; G01R33/38; G01R33/3806
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
68 words
An RF coil for the generation of a substantially homogeneous RF magnetic field for use in an MRI system having opposed magnet poles, said RF coil comprising: a pair of spaced apart flat pancake-like structures disposed on opposite sides of an imaging volume of the MRI system, each structure having a plurality of serially-connected turns including a plurality of juxtaposed conductor lengths having commonly directed current flows therein.
Claim 2
Dependent Claim
68 words
An RF coil for the generation of a substantially homogeneous RF magnetic field for use in an MRI system having opposed magnet poles, said RF coil comprising: a pair of spaced apart flat pancake-like structures disposed on opposite sides of an imaging volume of the MRI system, each structure having a plurality of serially-connected turns including a plurality of juxtaposed conductor lengths having commonly directed current flows therein.
Claim 3
Dependent Claim
36 words
An MRI RF coil as in claim 1 wherein: said turns of each structure are of even number with half being oriented in a clockwise sense and the other half being oriented in a counter-clockwise sense.
Claim 4
Dependent Claim
21 words
An MRI RF coil as in claim 1 wherein: said turns of each structure are disposed on a common, flat, substrate.
Claim 5
Dependent Claim
41 words
An MRI RF coil as in claim 3 wherein each structure further comprises a low-loss expanded dielectric spacer disposed on said substrate for maintaining a uniform predetermined spacing between the RF coil and magnetic field generating structures of the MRI system.
Claim 6
Dependent Claim
24 words
An MRI RF coil as in claim 1 wherein said turns of each structure are disposed in a D-shaped path and are substantially co-planar.
Claim 7
Dependent Claim
19 words
An RF coil as in claim I wherein said conductor lengths of each structure are substantially straight and parallel.
Claim 8
Dependent Claim
25 words
An RF coil as in claim 1, each said structure being spaced from magnetic gradient coils associated with opposed magnet poles of the MRI system.
Claim 9
Dependent Claim
37 words
An RF coil as in claim 7 in combination with a pair of tuning and impedance matching circuits, each being respectively connected to a corresponding one of the structures and to a common RF power splitting circuit.
Claim 10
Dependent Claim
71 words
An RF coil as in claim 8, further comprising: a pair of diode switch circuits, each being respectively connected in series with a corresponding one of the structures for effectively disconnecting said structures during at least RF receive times in an MRI data acquisition sequence; and a DC router circuit for connecting DC bias currents to said diode switch circuits while isolating RF currents from portions of the DC bias circuits.
Claim 11
Dependent Claim
87 words
An RF coil for use in an MRI system having opposed magnet poles, said RF coil comprising: a first substantially co-planar plurality of juxtaposed linear conductor lengths having commonly first directed current flows therein, and a second substantially co-planar plurality of juxtaposed linear conductor lengths having commonly second-directed current flows therein, said first and second conductor lengths each being separated from each other and disposed near a respectively associated one of said magnet poles and said first-directed current flows being disposed opposite to said second-directed current flows.
Claim 12
Dependent Claim
87 words
An RF coil for use in an MRI system having opposed magnet poles, said RF coil comprising: a first substantially co-planar plurality of juxtaposed linear conductor lengths having commonly first directed current flows therein, and a second substantially co-planar plurality of juxtaposed linear conductor lengths having commonly second-directed current flows therein, said first and second conductor lengths each being separated from each other and disposed near a respectively associated one of said magnet poles and said first-directed current flows being disposed opposite to said second-directed current flows.
Claim 13
Dependent Claim
37 words
An RF coil as in claim 10 wherein said linear conductor lengths comprise turns that are of even number with half being oriented in a clockwise sense and the other half being oriented in a counter-clockwise sense.
Claim 14
Dependent Claim
55 words
An RF coil as in claim 10 wherein said first and second conductor lengths are each disposed on a respectively associated substrate and further comprising a low-loss expanded dielectric spacer disposed on each said substrate for maintaining a uniform predetermined spacing between the RF coil and a magnetic field generating structure of the MRI system.
Claim 15
Dependent Claim
40 words
An RF coil as in claim 10 wherein said linear first conductor lengths are substantially straight and parallel with respect to each other and wherein said linear second conductor lengths are substantially straight and parallel with respect to each other.
Claim 16
Dependent Claim
72 words
An RF coil for use in an MRI system having opposed magnet poles, said RF coil comprising: a first flat pancake-like structure having a plurality of serially-connected, oppositely directed, turns including a plurality of juxtaposed linear conductor lengths having commonly directed current flows therein; and a second flat pancake-like structure having a plurality of serially-connected oppositely directed turns including a plurality of juxtaposed linear conductor lengths having commonly directed current flows therein.
Claim 17
Dependent Claim
72 words
An RF coil for use in an MRI system having opposed magnet poles, said RF coil comprising: a first flat pancake-like structure having a plurality of serially-connected, oppositely directed, turns including a plurality of juxtaposed linear conductor lengths having commonly directed current flows therein; and a second flat pancake-like structure having a plurality of serially-connected oppositely directed turns including a plurality of juxtaposed linear conductor lengths having commonly directed current flows therein.
Claim 18
Dependent Claim
35 words
An RF coil as in claim 14 wherein said turns of each structure are of even number with half being oriented in a clockwise sense and the other half being oriented in a counter-clockwise sense.
Claim 19
Dependent Claim
20 words
An RF coil as in claim 14 wherein said turns of each structure are disposed on a common, flat, substrate.
Claim 20
Dependent Claim
40 words
An RF coil as in claim 16 wherein each structure further comprises a low-loss expanded dielectric spacer disposed on its said substrate for maintaining a uniform predetermined spacing between the structures and magnetic field generating structures of the MRI system.
Claim 21
Dependent Claim
20 words
An RF coil as in claim 14 wherein said linear conductors lengths of each structure are substantially straight and parallel.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-01-30 | 1998-08-01 | 1999-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-01-30 | 2002-08-01 | 2003-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-01-30 | 2006-08-01 | 2007-01-31 | $7700.00 | Window Closed / Lapsed |