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US5485086A
Expired / Lapsed
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Continuous fluoroscopic MRI using spiral k-space scanning
Assignee: Leland Stanford Junior University
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Filing: 1994-07-26
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Granted: 1996-01-16
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Expires: 2014-07-26
Abstract
Abstract Continuous fluoroscopic data is acquired using magnetic resonance imaging by applying magnetic gradients to excited nuclei whereby emitted magnetic resonance signals traverse interleaved spirals in k-space. The spirals can have tighter loops near the origin of k-space to emphasize lower frequencies.
Inventors
- 👤 Craig H. Meyer
- 👤 Albert Macovski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 00:10
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/4818; G01R33/4824; G01R33/54; G01R33/56; G01R33/563; G01R33/56308; G01R33/446; G01R33/561; G01R33/5619
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
97 words
A method of acquiring continuous fluoroscopic data using magnetic resonance imaging comprising the steps of a) placing an object in a magnetic field, b) exciting nuclei in said object with an RF excitation pulse, c) applying magnetic gradients to said object whereby magnetic resonance signals emitted from said excited nuclei traverse a spiral in k-space, d) detecting magnetic resonance signals emitted from said exited nuclei, e) repeating steps b), c) and d) at different initial trajectories to create an interleaved set of spirals in k-space, and f) forming a fluoroscopic image based on said magnetic resonance signals.
Claim 2
Independent Claim
97 words
A method of acquiring continuous fluoroscopic data using magnetic resonance imaging comprising the steps of a) placing an object in a magnetic field, b) exciting nuclei in said object with an RF excitation pulse, c) applying magnetic gradients to said object whereby magnetic resonance signals emitted from said excited nuclei traverse a spiral in k-space, d) detecting magnetic resonance signals emitted from said exited nuclei, e) repeating steps b), c) and d) at different initial trajectories to create an interleaved set of spirals in k-space, and f) forming a fluoroscopic image based on said magnetic resonance signals.
Claim 3
Dependent Claim
28 words
The method as defined by claim 1 wherein said spirals in k-space has tighter loops near the origin of k-space whereby lower frequency signals are updated more rapidly.
Claim 4
Dependent Claim
18 words
The method as defined by claim 2 wherein step f) includes temporal filtering in forming said fluoroscopic image.
Claim 5
Dependent Claim
20 words
The method as defined by claim 3 wherein said step of temporal filtering includes selectively weighting said magnetic resonance signals.
Claim 6
Dependent Claim
18 words
The method as defined by claim 1 wherein step f) includes temporal filtering in forming said fluoroscopic image.
Claim 7
Dependent Claim
20 words
The method as defined by claim 5 wherein said step of temporal filtering includes selectively weighting said magnetic resonance signals.
Claim 8
Dependent Claim
108 words
Apparatus for acquiring continuous fluoroscopic data using magnetic resonance imaging comprising a) means for establishing a static magnetic field through an object, b) means for exciting nuclei in said object with RF excitation pulses, c) means for applying magnetic gradients to said object whereby magnetic resonance signals emitted from said excited nuclei traverse a spiral in k-space, d) means for detecting magnetic resonance signals emitted from said exited nuclei, e) said means for exciting and said means for applying magnetic gradients providing different initial trajectories to create an interleaved set of spirals in k-space, and f) means for forming a fluoroscopic image based on said magnetic resonance signals.
Claim 9
Dependent Claim
108 words
Apparatus for acquiring continuous fluoroscopic data using magnetic resonance imaging comprising a) means for establishing a static magnetic field through an object, b) means for exciting nuclei in said object with RF excitation pulses, c) means for applying magnetic gradients to said object whereby magnetic resonance signals emitted from said excited nuclei traverse a spiral in k-space, d) means for detecting magnetic resonance signals emitted from said exited nuclei, e) said means for exciting and said means for applying magnetic gradients providing different initial trajectories to create an interleaved set of spirals in k-space, and f) means for forming a fluoroscopic image based on said magnetic resonance signals.
Claim 10
Dependent Claim
40 words
Apparatus as defined by claim 7 wherein said means for applying magnetic gradients causes said magnetic resonance signals to traverse a spiral in k-space having tighter loops near the origin of k-space whereby lower frequency signals are updated more rapidly.
Claim 11
Dependent Claim
26 words
Apparatus as defined by claim 8 wherein said means for forming a fluoroscopic image includes a temporal filter for combining a plurality of magnetic resonance signals.
Claim 12
Dependent Claim
18 words
Apparatus as defined by claim 9 wherein said temporal filter selectively weights said plurality of magnetic resonance signals.
Claim 13
Dependent Claim
26 words
Apparatus as defined by claim 7 wherein said means for forming a fluoroscopic image includes a temporal filter for combining a plurality of magnetic resonance signals.
Claim 14
Dependent Claim
18 words
Apparatus as defined by claim 11 wherein said temporal filter selectively weights said plurality of magnetic resonance signals.
References Cited (Backward Citations)
US5402067A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-01-15 | 1999-07-17 | 2000-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-15 | 2003-07-17 | 2004-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-15 | 2007-07-17 | 2008-01-16 | $7700.00 | Window Closed / Lapsed |