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US5189371A
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Method and means for magnetic resonance imaging and spectroscopy using two-dimensional selective adiabatic PI pulses
Assignee: Leland Stanford Junior University
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Filing: 1991-08-08
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Granted: 1993-02-23
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Expires: 2011-08-08
Abstract
Abstract Two-dimensional selective adiabatic pulses invert magnetization from a square region in the xy plane with insensitivity to RF variations. Two-dimensional adiabatic pulses can also invert selectively in frequency and in one spatial dimension. The pulses are useful for both MR imaging and spectroscopy.
Inventors
- 👤 Steven M. Conolly
- 👤 John M. Pauly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:18
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/446
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
95 words
A method of inverting a region in the plane of an object using selective adiabatic nuclear magnetic resonance RF pulses comprising the steps of a) placing said object in a static magnetic field, b) applying a sequence of one dimensional selective sub-pulses, said sub-pulses rotating spins with nearly identical rotation profiles, each sub-pulse having a rotation angle determined by sampling of one of said adiabatic nuclear magnetic resonance RF pulses, and c) concurrently with step (b) applying a time varying magnetic gradient along said one axis (x) and consistent with each of said RF sub-pulses.
Claim 2
Independent Claim
95 words
A method of inverting a region in the plane of an object using selective adiabatic nuclear magnetic resonance RF pulses comprising the steps of a) placing said object in a static magnetic field, b) applying a sequence of one dimensional selective sub-pulses, said sub-pulses rotating spins with nearly identical rotation profiles, each sub-pulse having a rotation angle determined by sampling of one of said adiabatic nuclear magnetic resonance RF pulses, and c) concurrently with step (b) applying a time varying magnetic gradient along said one axis (x) and consistent with each of said RF sub-pulses.
Claim 3
Dependent Claim
35 words
The method as defined by claim 1 and further including the following step: (d) applying a plurality of magnetic gradient lobes along another axis (y) with each lobe centered at a null between said sub-pulses.
Claim 4
Dependent Claim
21 words
The method as defined by claim 2 and further including the following step: (e) detecting signals from nuclei in said region.
Claim 5
Dependent Claim
25 words
The method as defined by claim 1 wherein step (c) includes alternating polarity of said magnetic gradient along said one axis (x) for successive sub-pulses.
Claim 6
Dependent Claim
25 words
The method as defined by claim 4 wherein said magnetic gradient along said one axis (x) has a generally W-shaped magnitude configuration for each polarity.
Claim 7
Dependent Claim
25 words
The method as defined by claim 4 wherein said magnetic gradient along said one axis (x) has a generally triangular-shaped magnitude configuration for each polarity.
Claim 8
Dependent Claim
95 words
Apparatus for inverting a region in the plane of an object using selective adiabatic nuclear magnetic resonance RF pulses comprising a) means for establishing a static magnetic field along one axis (z), b) means for applying a sequence of one dimensional selective sub-pulses, said sub-pulses rotating spins with nearly identical rotation profiles, each sub-pulses having a rotation angle determined by sampling of one of said adiabatic nuclear magnetic resonance RF pulses, and c) means for concurrently applying a time varying magnetic gradient along said one axis (x) and consistent with each of said RF sub-pulses.
Claim 9
Dependent Claim
95 words
Apparatus for inverting a region in the plane of an object using selective adiabatic nuclear magnetic resonance RF pulses comprising a) means for establishing a static magnetic field along one axis (z), b) means for applying a sequence of one dimensional selective sub-pulses, said sub-pulses rotating spins with nearly identical rotation profiles, each sub-pulses having a rotation angle determined by sampling of one of said adiabatic nuclear magnetic resonance RF pulses, and c) means for concurrently applying a time varying magnetic gradient along said one axis (x) and consistent with each of said RF sub-pulses.
Claim 10
Dependent Claim
36 words
Apparatus as defined by claim 7 and further including the following step: d) means for applying a plurality of magnetic gradient lobes along another axis (y) with each lobe centered at a null between said sub-pulses.
Claim 11
Dependent Claim
18 words
Apparatus as defined by claim 7 and further including means for detecting signals from nuclei in said region.
Claim 12
Dependent Claim
33 words
Apparatus as defined by claim 7 wherein said means for applying a magnetic gradient along said one axis (x) alternates polarity of said magnetic gradient along said one axis (x) for successive sub-pulses.
Claim 13
Dependent Claim
27 words
Apparatus as defined by claim 7 wherein said means for applying a magnetic gradient along said one axis (x) alternates polarity of said gradient for successive sub-pulses.
Claim 14
Dependent Claim
24 words
Apparatus as defined by claim 11 wherein said magnetic gradient along said one axis (x) has a generally W-shaped magnitude configuration for each polarity.
Claim 15
Dependent Claim
24 words
Apparatus as defined by claim 11 wherein said magnetic gradient along said one axis (x) has a generally triangular-shaped magnitude configuration for each polarity.
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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) | 1996-02-23 | 1996-08-24 | 1997-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-02-23 | 2000-08-24 | 2001-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-02-23 | 2004-08-24 | 2005-02-23 | $7700.00 | Window Closed / Lapsed |