US5545992A
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Fast cardiac gated NMR acquisition with improved T1 contrast
Assignee: General Electric Co
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Filing: 1995-08-03
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Granted: 1996-08-13
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Expires: 2015-08-03
Abstract
Abstract A fast gradient echo, cardiac gated NMR scan is performed by acquiring groups of views during each cardiac cycle. Each group of views is preceded by an accelerator RF pulse and disdaq pulse sequences to improve T 1 contrast and drive spin magnetization rapidly to dynamic equilibrium.
Inventors
- 👤 Thomas K. Foo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:57
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/54; G01R33/56; G01R33/561; G01R33/5613; G01R33/5615; G01R33/5616; G01R33/567; G01R33/5673
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
114 words
A method for acquiring NMR data to produce an image of a subject with improved contrast, the step comprising: a) subjecting the subject to a polarizing magnetic field; b) applying an accelerator RF field to the subject having a flip-angle in the range of 60° to 140°; c) performing a disdaq pulse sequence which includes applying an RF field to the subject having a flip-angle substantially less than the flip-angle of the accelerator RF field; d) performing a series of NMR measurements in which transverse magnetization is produced by an excitation RF field and an NMR signal produced by the transverse magnetization is acquired; and e) reconstructing an image from the acquired NMR signals.
Claim 2
Independent Claim
114 words
A method for acquiring NMR data to produce an image of a subject with improved contrast, the step comprising: a) subjecting the subject to a polarizing magnetic field; b) applying an accelerator RF field to the subject having a flip-angle in the range of 60° to 140°; c) performing a disdaq pulse sequence which includes applying an RF field to the subject having a flip-angle substantially less than the flip-angle of the accelerator RF field; d) performing a series of NMR measurements in which transverse magnetization is produced by an excitation RF field and an NMR signal produced by the transverse magnetization is acquired; and e) reconstructing an image from the acquired NMR signals.
Claim 3
Dependent Claim
23 words
The method as recited in claim 1 in which a plurality of disdaq pulse sequences are performed prior to performing the NMR measurements.
Claim 4
Dependent Claim
19 words
The method as recited in claim 1 in which the accelerator RF field has a flip-angle of substantially 90°.
Claim 5
Dependent Claim
25 words
The method as recited in claim 1 in which the series of NMR measurements are performed using a series of fast gradient echo pulse sequences.
Claim 6
Dependent Claim
20 words
The method as recited in claim 4 in which the disdaq pulse sequence is a fast gradient echo pulse sequence.
Claim 7
Dependent Claim
24 words
The method as recited in claim 5 in which the accelerator RF field is applied as part of a fast gradient echo pulse sequence.
Claim 8
Dependent Claim
29 words
The method as recited in claim 1 in which steps a) through d) are performed a plurality of times before an image is reconstructed from the acquired NMR signals.
Claim 9
Dependent Claim
20 words
The method as recited in claim 1 in which a plurality of disdaq pulse sequences are performed in step c).
Claim 10
Dependent Claim
18 words
The method as recited in claim 1 in which two disdaq pulse sequences are performed in step c).
Claim 11
Dependent Claim
27 words
The method as recited in claim 8 in which the series of NMR measurements performed in step d) are a series of fast gradient echo pulse sequences.
Claim 12
Dependent Claim
17 words
The method as recited in claim 10 in which eight fast gradient echo pulse sequences are performed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-08-13 | 2000-02-12 | 2000-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-08-13 | 2004-02-12 | 2004-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-08-13 | 2008-02-12 | 2008-08-13 | $7700.00 | Window Closed / Lapsed |