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US5363036A
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Echo-volumar imaging using 180 degree RF pulses
Assignee: BTG International Ltd
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Filing: 1991-07-30
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Granted: 1994-11-08
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Expires: 2011-07-30
Abstract
Abstract A method of producing a magnetic resonance image of a defined region of an object by an echo volumar imaging process including subjecting the object to an initial selection process to select a thick slice within the object to produce an active volume of spin magnetisation subjecting the active volume so defined to a combination of 180° RF pulses and suitably modulated x, y and z gradients to produce an echo volumar image.
Inventors
- 👤 Peter Mansfield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:13
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/54; G01R33/56; G01R33/561; G01R33/5615; F; F02; F02G; F02G1/00; F02G1/04; F02G1/043; F02G1/044; F02G1/0445; F02G2250/00; F02G2250/18; G01R33/4818; G01R33/482; G01R33/4822; G01R33/5618
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
78 words
A method of producing a magnetic resonance three-dimensional image of a defined region of an object by an echo volumar imaging process, comprising the steps of: subjecting the object to an initial selection process to select a thick slice within the object to produce an active volume of spin magnetisation; and subjecting the active volume so defined to a combination of 180° RF pulses and modulated x, y and z gradients to produce an echo volumar three-dimensional image.
Claim 2
Independent Claim
78 words
A method of producing a magnetic resonance three-dimensional image of a defined region of an object by an echo volumar imaging process, comprising the steps of: subjecting the object to an initial selection process to select a thick slice within the object to produce an active volume of spin magnetisation; and subjecting the active volume so defined to a combination of 180° RF pulses and modulated x, y and z gradients to produce an echo volumar three-dimensional image.
Claim 3
Dependent Claim
91 words
A method of producing a magnetic resonance image of a defined region of an object by an echo volumar imaging process as claimed in claim 1 in which the combination of the modulated x, y and z gradients (G x , G y , G z ) and the 180° RF pulses produces a complex trajectory in k-space which ensures that signal data obtained in such a sequence is ordered such that a Fourier transform is able to reconstitute a three dimensional image set from the three dimensional k-space data set.
Claim 4
Dependent Claim
48 words
A method of producing a magnetic resonance image of a defined region of an object by an echo volumar imaging process as claimed in claim 2 in which the x gradient (G x ) is monopolar with small gaps (or windows) within which the RF pulses are applied.
Claim 5
Dependent Claim
59 words
A method of producing a magnetic resonance image of a defined region of an object by an echo volumar imaging process as claimed in claim 3 in which the modulated y gradient (G y ) comprises a series of short blips which are arranged to fall in alternate G x gaps but not to coincide with the RF pulses.
Claim 6
Dependent Claim
41 words
A method of producing a magnetic resonance image of a defined region of an object by an echo volumar imaging process as claimed in claim 4 in which the G y blips precede the RF pulses within the G x gaps.
Claim 7
Dependent Claim
58 words
A method of producing a magnetic resonance image of a defined region of an object by an echo volumar imaging process as claimed in claim 5 in which the modulated z gradient (G z ) is applied as a series of blipped pulses at predetermined intervals the G z pulses being less frequent than the G y pulses.
Claim 8
Dependent Claim
44 words
A method of producing a magnetic resonance image of a defined region of an object by an echo volumar imaging process as claimed in claim 6 in which the G z pulses precede the RF pulses within the gaps in the G x pulses.
Claim 9
Dependent Claim
72 words
A method of producing a magnetic resonance image of a defined region of an object by an echo volumar imaging process as claimed in claim 2 in which the x gradient (G x ) is modulated for a short period to provide spatial encoding along the x-axis and in which the y gradient (G y ) is applied in short blips at points corresponding to the zero crossings of G x .
Claim 10
Dependent Claim
61 words
A method of producing a magnetic resonance image of a defined region of an object by an echo volumar imaging process as claimed in claim 8 in which the modulated z gradient (G z ) pulses are applied during periods in which the G x gradient is zero; the G z pulses being applied less frequently than the G y pulses.
Claim 11
Dependent Claim
67 words
A method of producing a magnetic resonance image of a defined region of an object by an echo volumar imaging process as claimed in claim 2 in which the modulated y gradient G y is applied in the form of a square or trapezoidally modulated waveform and in which the modulated z gradient (G z ) is applied in the form of a constant low level waveform.
Claim 12
Dependent Claim
65 words
A method of producing a magnetic resonance image of a defined region of an object by an echo volumar imaging process as claimed in claim 2 in which the modulated y gradient (G y ) is applied in the form of a low level waveform and in which the modulated z gradient G z is applied in the form of a constant low level waveform.
References Cited (Backward Citations)
EP0091008A2
Cited
US4716369A
Cited
US4818940A
Cited
US4684891A
Cited
US4698592A
Cited
EP0240319A2
Cited
US4746864A
Cited
US4799013A
Cited
WO1991002263A1
Cited
US5221898A
Cited
US5212448A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-11-07 | 1998-05-09 | 1998-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-11-07 | 2002-05-09 | 2002-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-11-07 | 2006-05-09 | 2006-11-08 | $7700.00 | Window Closed / Lapsed |