US4777439A
Expired / Lapsed
US
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Spatially localized spectroscopy
Assignee: General Electric Co
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Filing: 1987-03-20
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Granted: 1988-10-11
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Expires: 2007-03-20
Abstract
Abstract A method of obtaining spatially localized spectroscopic signals by using RF pulse sequences in the presence or gradient fields to generate stimulated echoes.
Inventors
- 👤 Joseph Granot
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:34
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/446; G01R33/48; G01R33/483; G01R33/4833
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
187 words
A method for performing localized NMR shift spectroscopy comprising the steps of: aligning spins in an in-vivo sample by positioning the sample in a homogeneous magnetic field for obtaining NMR derived data from the sample, irradiating said sample with a first 90 degree RF pulse in the presence of a first magnetic gradient so as to nutate the aligned spins in a first selected volume of said sample, irradiating said sample with a second 90 degree RF pulse in the presence of a second magnetic gradient normal to said first magnetic gradient so as to further nutate the aligned spins in a portion of said first selected volume of said sample, irradiating said sample with a third 90 degree RF pulse in the presence of a third magnetic gradient normal to said first and second magnetic gradients to still further nutate the further nutated spins in a section of said portion of said first selected volume, to thereby select a particular volume of the sample, and selecting said first, second and third 90 degree RF pulses to generate stimulated echo signals from said still further nutated spins.
Claim 2
Independent Claim
187 words
A method for performing localized NMR shift spectroscopy comprising the steps of: aligning spins in an in-vivo sample by positioning the sample in a homogeneous magnetic field for obtaining NMR derived data from the sample, irradiating said sample with a first 90 degree RF pulse in the presence of a first magnetic gradient so as to nutate the aligned spins in a first selected volume of said sample, irradiating said sample with a second 90 degree RF pulse in the presence of a second magnetic gradient normal to said first magnetic gradient so as to further nutate the aligned spins in a portion of said first selected volume of said sample, irradiating said sample with a third 90 degree RF pulse in the presence of a third magnetic gradient normal to said first and second magnetic gradients to still further nutate the further nutated spins in a section of said portion of said first selected volume, to thereby select a particular volume of the sample, and selecting said first, second and third 90 degree RF pulses to generate stimulated echo signals from said still further nutated spins.
Claim 3
Dependent Claim
11 words
The method of claim 1 wherein said pulses are shaped pulses.
Claim 4
Dependent Claim
22 words
The method of claim 1 including the step of extending said second magnetic gradient beyond the second RF pulse to destroy coherence.
Claim 5
Dependent Claim
54 words
The method of claim 1 including the steps of: applying the stimulated echo sequence at least twice, inverting the phase of the first RF pulse for the second application of the sequence, and subtracting the signal acquired using the inverted phase from the signal acquired with the non-inverted phase to thereby cancel transverse magnetization.
Claim 6
Dependent Claim
51 words
The method of claim 4 including the steps of: selecting the position of each of the selected volumes by selecting the frequency of the RF pulses; selecting the sizes of each of the selected volumes by selecting the bandwidth of the RF pulses, and selecting the amplitudes of the RF pulses.
Claim 7
Independent Claim
269 words
The method for performing NMR shift spectroscopy comprising the steps of: aligning spins in a sample by positioning the sample in a homogeneous magnetic field for obtaining NMR derived spectroscopic data from the sample, said homogeneous magnetic field extending in the Z direction of an imaginary XYZ orthogonal coordinate system, irradiating said sample with a first 90 degree RF pulse in the presence of a first magnetic gradient so as to nutate the aligned spins into a slab in said sample, said slab being perpendicular to said Z direction, irradiating said sample with a second 90 degree RF pulse in the presence of a second magnetic gradient normal to said first magnetic gradient so as to further nutate the nutated spins in a first strip in said slab, irradiating said sample with a third 90 degree RF pulse in the presence of a third magnetic gradient normal to said first and second magnetic gradients to still further nutate the further nutated spins in a second strip in said slab, said second strip being normal to said first strip so that the selected volume is the intersection of the first strip and the second strip in said slab in said sample, said first, second and third RF pulses generating a stimulated echo signal from said still further nutated spins in said selected volume of said sample, and acquiring signals from other localized volumes of said sample during the same scan sequence by using the same sequence of steps during the time period between the receipt of the simulated echo signal until the spins substantially realign with the homogeneous magnetic field.
Claim 8
Independent Claim
269 words
The method for performing NMR shift spectroscopy comprising the steps of: aligning spins in a sample by positioning the sample in a homogeneous magnetic field for obtaining NMR derived spectroscopic data from the sample, said homogeneous magnetic field extending in the Z direction of an imaginary XYZ orthogonal coordinate system, irradiating said sample with a first 90 degree RF pulse in the presence of a first magnetic gradient so as to nutate the aligned spins into a slab in said sample, said slab being perpendicular to said Z direction, irradiating said sample with a second 90 degree RF pulse in the presence of a second magnetic gradient normal to said first magnetic gradient so as to further nutate the nutated spins in a first strip in said slab, irradiating said sample with a third 90 degree RF pulse in the presence of a third magnetic gradient normal to said first and second magnetic gradients to still further nutate the further nutated spins in a second strip in said slab, said second strip being normal to said first strip so that the selected volume is the intersection of the first strip and the second strip in said slab in said sample, said first, second and third RF pulses generating a stimulated echo signal from said still further nutated spins in said selected volume of said sample, and acquiring signals from other localized volumes of said sample during the same scan sequence by using the same sequence of steps during the time period between the receipt of the simulated echo signal until the spins substantially realign with the homogeneous magnetic field.
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) | 1991-10-11 | 1992-04-11 | 1992-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-11 | 1996-04-11 | 1996-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-11 | 2000-04-11 | 2000-10-11 | $7700.00 | Window Closed / Lapsed |