US5347220A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic resonance apparatus comprising a bird-cage RF coil
Assignee: US Philips Corp
•
Filing: 1992-12-09
•
Granted: 1994-09-13
•
Expires: 2012-12-09
Abstract
Abstract A magnetic resource apparatus includes a mainly cylindrical RF coil (9) having a longitudinal directed central axis (33) and symmetry plane (35) which contains the central axis and a reference plane (37). The reference plane extends perpendicularly to the symmetry plane and also contains the central axis. The coil (9) has a number of rod conductors (39) which extend, parallel to the central axis (33), across a mainly cylindrical surface, and loop conductors (41) which extend around the central axis near the ends of the rod conductors, the length of the rod conductors (39) situated near the symmetry plane (35) being greater than that of the rod conductors situated near the reference plane (37). In order to enable sharp and low-noise images to be made of the neck of a patient, the rod conductors (39) which are situated near the symmetry plane (35) and to one side of the reference plane (37) have a length which is greater than that of the rod conductors situated near the symmetry plane and to the other side of the reference plane.
Inventors
- 👤 Teunis R. van Heelsbergen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:21
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/34; G01R33/34046
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
188 words
A magnetic resonance apparatus, comprising a mainly cylindrical RF coil having a longitudinally directed central axis and a mutually perpendicular symmetry plane and reference plane which intersect each other along the central axis, and also comprises a plurality of rod conductors which extend parallel to the central axis across a mainly cylindrical surface, and loop conductors which extend around the central axis near the ends of the rod conductors, said plurality of rod conductors including rod conductors which are situated diametrically near the symmetry plane on opposite sides of the reference plane and rod conductors which are situated diametrically near the reference plane on opposite sides of the symmetry plane, the reference plane on opposite sides of the symmetry plane, the rod conductors situated near the symmetry plane on opposite sides of the reference plane being longer than the rod conductors situated near the reference plane on opposite sides of the symmetry plane, and the rod conductors situated near the symmetry plane on one side of the reference plane being longer than the rod conductors situated near the symmetry plane on the other side of the reference plane.
Claim 2
Dependent Claim
188 words
A magnetic resonance apparatus, comprising a mainly cylindrical RF coil having a longitudinally directed central axis and a mutually perpendicular symmetry plane and reference plane which intersect each other along the central axis, and also comprises a plurality of rod conductors which extend parallel to the central axis across a mainly cylindrical surface, and loop conductors which extend around the central axis near the ends of the rod conductors, said plurality of rod conductors including rod conductors which are situated diametrically near the symmetry plane on opposite sides of the reference plane and rod conductors which are situated diametrically near the reference plane on opposite sides of the symmetry plane, the reference plane on opposite sides of the symmetry plane, the rod conductors situated near the symmetry plane on opposite sides of the reference plane being longer than the rod conductors situated near the reference plane on opposite sides of the symmetry plane, and the rod conductors situated near the symmetry plane on one side of the reference plane being longer than the rod conductors situated near the symmetry plane on the other side of the reference plane.
Claim 3
Dependent Claim
47 words
A magnetic resonance apparatus as claimed in claim 1, wherein a distance between rod conductors situated near the reference plane on opposite sides of the symmetry plane is smaller than a distance between rod conductors situated near the symmetry plane on opposite sides of the reference plane.
Claim 4
Dependent Claim
58 words
A magnetic resonance apparatus as claimed in claim 1, characterized in that at least one capacitive element is connected in series with each rod conductor, such that a capacitance in series with each of the rod conductors near the symmetry plane is greater than a capacitance in series with each of the rod conductors near the reference plane.
Claim 5
Dependent Claim
67 words
A magnetic resonance apparatus as claimed in claim 1, in which the RF coil comprises first and second connection means for connecting the RF coil to transmitter or receiver means for excitation or reception, respectively utilizing first and second resonant modes of the RF coil, further comprising switching means for selectively deactivating a connection between one of the two connection means and the transmitter or receiver means.
Claim 6
Dependent Claim
184 words
An RF coil suitable for use in a magnetic resonance apparatus, said coil being mainly cylindrical, having a longitudinally directed central axis and a mutually perpendicular symmetry plane and reference plane which intersect each other along the central axis, and also comprises a plurality of rod conductors which extend parallel to the central axis across a mainly cylindrical surface, and loop conductors which extend around the central axis near the ends of the rod conductors, said plurality of rod conductors including rod conductors which are situated diametrically near the symmetry plane on opposite sides of the reference plane and rod conductors which are situated diametrically near the reference plane on opposite sides of the symmetry plane, the rod conductors situated near the symmetry plane on opposite sides of the reference plane being longer than the rod conductors situated near the reference plane on opposite sides of the symmetry plane, and the rod conductors situated near the symmetry plane on one side of the reference plane being longer than the rod conductors situated near the symmetry plane on the other side of the reference plane.
Claim 7
Dependent Claim
184 words
An RF coil suitable for use in a magnetic resonance apparatus, said coil being mainly cylindrical, having a longitudinally directed central axis and a mutually perpendicular symmetry plane and reference plane which intersect each other along the central axis, and also comprises a plurality of rod conductors which extend parallel to the central axis across a mainly cylindrical surface, and loop conductors which extend around the central axis near the ends of the rod conductors, said plurality of rod conductors including rod conductors which are situated diametrically near the symmetry plane on opposite sides of the reference plane and rod conductors which are situated diametrically near the reference plane on opposite sides of the symmetry plane, the rod conductors situated near the symmetry plane on opposite sides of the reference plane being longer than the rod conductors situated near the reference plane on opposite sides of the symmetry plane, and the rod conductors situated near the symmetry plane on one side of the reference plane being longer than the rod conductors situated near the symmetry plane on the other side of the reference plane.
Claim 8
Dependent Claim
58 words
A magnetic resonance apparatus as claimed in claim 2, characterized in that at least one capacitive element is connected in series with each rod conductor, such that a capacitance in series with each of the rod conductors near the symmetry plane is greater than a capacitance in series with each of the rod conductors near the reference plane.
Claim 9
Dependent Claim
67 words
A magnetic resonance apparatus as claimed in claim 6, in which the RF coil comprises first and second connection means for connecting the RF coil to transmitter or receiver means for excitation or reception, respectively, utilizing first and second resonant modes of the RF coil, further comprising switching means for selectively deactivating a connection between one of the two connection means and the transmitter or receiver means.
References Cited (Backward Citations)
EP0141383A2
Cited
US4879516A
Cited
US5045792A
Cited
US4737718A
Cited
US4784146A
Cited
US4820985A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-09-12 | 1998-03-14 | 1998-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-09-12 | 2002-03-14 | 2002-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-09-12 | 2006-03-14 | 2006-09-13 | $7700.00 | Window Closed / Lapsed |