US5302901A
Expired / Lapsed
US
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Magnetic resonance apparatus comprising decoupled receiver coils
Assignee: US Philips Corp
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Filing: 1992-08-20
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Granted: 1994-04-12
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Expires: 2012-08-20
Abstract
Abstract Magnetic resonance apparatus includes an RF receiver coil system (13, 15) for detecting magnetic resonance signals generated in an object. This RF receiver coil system has a first (35) and a second receiver coil (37) which could be coupled to one another by mutual inductance. In order to compensate for the mutual inductance there is provided a decoupling network. This network has a first (49) and a second terminal (51) which are connected to a first end and a second end, respectively, of the first receiver coil (35), and also a third (53) and a fourth terminal (55) which are connected to a first end and a second end, respectively, of the second receiver coil (37). The decoupling network contains a first circuit (57) of variable impedance which interconnects the first and the third terminal (49, 53) and also a second circuit (59) of variable impedance which interconnects the second and the fourth terminal (51, 55). Each of the first and second circuits (57, 59) have at least one capacitor ( 63) and at least one coil (61), the value of the capacitor and/or the coil being variable so as to enable variation of the impedance of the circuits.
Inventors
- 👤 Jeroen Snelten
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:19
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/36; G01R33/3642; G01R33/365
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
205 words
A magnetic resonance apparatus comprising a magnet system for generating a steady magnetic field, a coil system for generating a gradient field, an RF transmitter coil, and an RF receiver coil system for detecting magnetic resonance signals generated in an object, which RF receiver coil system comprises first and second receiver coils which are coupled to one another by an unwanted coupling due to mutual inductance, and a decoupling network means for producing a compensation coupling between said first and second coils which is opposite in sign and substantially equal in magnitude to said unwanted coupling due to mutual inductance, which network means comprises first and second terminals which are connected to opposite ends, respectively, of the first receiver coil and third and fourth terminals which are connected to opposite ends, respectively, of the second receiver coil, said decoupling network means comprising a first circuit of variable impedance which interconnects the first and third terminals and a second circuit of variable impedance which interconnects the second and fourth terminals, said first and second circuits being variable in impedance over a range including both inductive and capacitive reactance such that the compensation coupling produced by said decoupling network means is variable in both sign and magnitude.
Claim 2
Dependent Claim
205 words
A magnetic resonance apparatus comprising a magnet system for generating a steady magnetic field, a coil system for generating a gradient field, an RF transmitter coil, and an RF receiver coil system for detecting magnetic resonance signals generated in an object, which RF receiver coil system comprises first and second receiver coils which are coupled to one another by an unwanted coupling due to mutual inductance, and a decoupling network means for producing a compensation coupling between said first and second coils which is opposite in sign and substantially equal in magnitude to said unwanted coupling due to mutual inductance, which network means comprises first and second terminals which are connected to opposite ends, respectively, of the first receiver coil and third and fourth terminals which are connected to opposite ends, respectively, of the second receiver coil, said decoupling network means comprising a first circuit of variable impedance which interconnects the first and third terminals and a second circuit of variable impedance which interconnects the second and fourth terminals, said first and second circuits being variable in impedance over a range including both inductive and capacitive reactance such that the compensation coupling produced by said decoupling network means is variable in both sign and magnitude.
Claim 3
Dependent Claim
29 words
A magnetic resonance apparatus as claimed in claim 1, wherein the first and second circuits comprise respective parallel connected circuits, each having a respective coil and a respective capacitor.
Claim 4
Dependent Claim
28 words
A magnetic resonance apparatus as claimed in claim 2, wherein the first receiver coil is a butterfly coil and the second receiver coil is a substantially flat coil.
Claim 5
Dependent Claim
33 words
A magnetic resonance apparatus as claimed in claim 2, wherein the respective capacitors comprised by the first and second circuits are variable and have respective control members which are coupled to one another.
Claim 6
Dependent Claim
33 words
A magnetic resonance apparatus as claimed in claim 2, wherein the respective coils comprised by the first and second circuits are variable and have respective control members which are coupled to one another.
Claim 7
Dependent Claim
28 words
A magnetic resonance apparatus as claimed in claim 1, wherein the first receiver coil is a butterfly coil and the second receiver coil is a substantially flat coil.
Claim 8
Dependent Claim
178 words
An RF receiver coil system suitable for use in a magnetic resonance apparatus, which RF receiver coil system comprises first and second receiver coils which are coupled to one another by an unwanted coupling due to mutual inductance, and a decoupling network means for producing a compensation coupling between said first and second coils which is opposite in sign and substantially equal in magnitude to said unwanted coupling due to mutual inductance, which network means comprises first and second terminals which are connected to opposite ends, respectively, of the first receiver coil and third and fourth terminals which are connected to opposite ends, respectively, of the second receiver coil, said decoupling network means comprising a first circuit of variable impedance which interconnects the first and third terminals and a second circuit of variable impedance which interconnects the second and fourth terminals, said first and second circuits being variable in impedance over a range that includes both inductive and capacitive reactance such that the compensation coupling produced by said decoupling network means is variable in both sign and magnitude.
Claim 9
Dependent Claim
178 words
An RF receiver coil system suitable for use in a magnetic resonance apparatus, which RF receiver coil system comprises first and second receiver coils which are coupled to one another by an unwanted coupling due to mutual inductance, and a decoupling network means for producing a compensation coupling between said first and second coils which is opposite in sign and substantially equal in magnitude to said unwanted coupling due to mutual inductance, which network means comprises first and second terminals which are connected to opposite ends, respectively, of the first receiver coil and third and fourth terminals which are connected to opposite ends, respectively, of the second receiver coil, said decoupling network means comprising a first circuit of variable impedance which interconnects the first and third terminals and a second circuit of variable impedance which interconnects the second and fourth terminals, said first and second circuits being variable in impedance over a range that includes both inductive and capacitive reactance such that the compensation coupling produced by said decoupling network means is variable in both sign and magnitude.
Claim 10
Dependent Claim
30 words
An RF receiver coil system as claimed in claim 7, wherein the first and second circuits comprise respective parallel connected circuits, each having a respective coil and a respective capacitor.
Claim 11
Dependent Claim
29 words
An RF receiver coil system as claimed in claim 8, wherein the first receiver coil is a butterfly coil and the second receiver coil is a substantially flat coil.
Claim 12
Dependent Claim
34 words
An RF receiver coil system as claimed in claim 8, wherein the respective capacitors comprised by the first and second circuits are variable and have respective control members which are coupled to one another.
Claim 13
Dependent Claim
34 words
An RF receiver coil system as claimed in claim 8, wherein the respective coils comprised by the first and second circuits are variable and have respective control members which are coupled to one another.
Claim 14
Dependent Claim
29 words
An RF receiver coil system as claimed in claim 6, wherein the first receiver coil is a butterfly coil and the second receiver coil is a substantially flat coil.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-04-11 | 1997-10-11 | 1998-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-04-11 | 2001-10-11 | 2002-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-04-11 | 2005-10-11 | 2006-04-12 | $7700.00 | Window Closed / Lapsed |