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US5539313A
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Full echo spiral-in/spiral-out magnetic resonance imaging
Assignee: Leland Stanford Junior University
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Filing: 1995-08-04
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Granted: 1996-07-23
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Expires: 2015-08-04
Abstract
Abstract T 2 -weighted interleaved spiral scanning is employed for imaging abdominal tumors. The gradients scan k-space in a spiral-in and spiral-out sequence with a first spiral starting at the edge of k-space and reaching the origin at signal echo time and then spiraling out to the edge of k-space preferably as a k-space conjugate of the inward spiral. A set of interleaves rotated through 180° contains sufficient data to reconstruct an image. Rotating through a full 360° provides additional insensitivity to T 2 decay, inhomogeneity, and flow.
Inventors
- 👤 Craig H. Meyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:53
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/446; G01R33/48; G01R33/54
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
96 words
A method of magnetic resonance imaging comprising the steps of a) positioning a body to be imaged in a static magnetic field; b) applying RF excitation pulses in the presence of a magnetic gradient for image slice selection; c) applying magnetic gradients during signal read-out so that the gradients scan k-space in a spiral-in and spiral-out sequence with a first spiral starting at an edge of k-space and reaching the origin at signal echo time and then a second spiral moves from the origin out to the edge of k-space; and d) detecting an echo signal.
Claim 2
Independent Claim
96 words
A method of magnetic resonance imaging comprising the steps of a) positioning a body to be imaged in a static magnetic field; b) applying RF excitation pulses in the presence of a magnetic gradient for image slice selection; c) applying magnetic gradients during signal read-out so that the gradients scan k-space in a spiral-in and spiral-out sequence with a first spiral starting at an edge of k-space and reaching the origin at signal echo time and then a second spiral moves from the origin out to the edge of k-space; and d) detecting an echo signal.
Claim 3
Dependent Claim
19 words
The method as defined by claim 1 wherein said second spiral is the k-space conjugate of said first spiral.
Claim 4
Dependent Claim
20 words
The method as defined by claim 2 wherein steps c) and d) are repeated to obtain multiple interleaved k-space scans.
Claim 5
Dependent Claim
20 words
The method as defined by claim 1 wherein steps c) and d) are repeated to obtain multiple interleaved k-space scans.
Claim 6
Dependent Claim
100 words
Apparatus for magnetic resonance imaging comprising a) means for applying a static magnetic field in a body to be imaged; b) means for applying RF excitation pulses in the presence of a magnetic gradient for image slice selection; c) means for applying magnetic gradients during signal read-out so that the gradients scan k-space in a spiral-in and spiral-out sequence with a first spiral starting at an edge of k-space and reaching the origin at signal echo time and then a second spiral moves from the origin out to the edge of k-space; and d) means for detecting an echo signal.
Claim 7
Dependent Claim
100 words
Apparatus for magnetic resonance imaging comprising a) means for applying a static magnetic field in a body to be imaged; b) means for applying RF excitation pulses in the presence of a magnetic gradient for image slice selection; c) means for applying magnetic gradients during signal read-out so that the gradients scan k-space in a spiral-in and spiral-out sequence with a first spiral starting at an edge of k-space and reaching the origin at signal echo time and then a second spiral moves from the origin out to the edge of k-space; and d) means for detecting an echo signal.
Claim 8
Dependent Claim
18 words
Apparatus as defined by claim 5 wherein said second spiral is the k-space conjugate of said first spiral.
Claim 9
Dependent Claim
32 words
Apparatus as defined by claim 6 wherein said means for applying magnetic gradients periodically applies magnetic gradients so that said means for detecting detects echo signals corresponding to multiple interleaved k-space scans.
Claim 10
Dependent Claim
32 words
Apparatus as defined by claim 5 wherein said means for applying magnetic gradients periodically applies magnetic gradients so that said means for detecting detects echo signals corresponding to multiple interleaved k-space scans.
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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) | 1999-07-23 | 2000-01-22 | 2000-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-23 | 2004-01-22 | 2004-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-23 | 2008-01-22 | 2008-07-23 | $7700.00 | Window Closed / Lapsed |