US4803432A
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Short echo NMR imaging of sodium
Assignee: Wisconsin Alumni Research Foundation
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Filing: 1987-08-13
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Granted: 1989-02-07
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Expires: 2007-08-13
Abstract
Abstract An NMR pulse sequence includes a nonselective RF excitation pulse followed by one or more nonselective echo RF pulses which produce NMR echo signals at echo times starting at TE=2.5 milliseconds. This short echo time enables paramagnetic nuclei having short T 2 relaxation components, such as sodium 23 , to be measured and imaged. Presaturation pulses at the beginning of the NMR pulse sequence serve as an alternative to slice selection.
Inventors
- 👤 William H. Perman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:02
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/4816; G01R33/50; G01R33/54; G01R33/56; G01R33/561
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
121 words
A method of producing an NMR signal from paramagnetic nuclei having a short T 2 relaxation constant, the steps comprising: applying a selective RF saturation pulse in combination with a magnetic field gradient to saturate paramagnetic nuclei on each side of a selected slice of paramagnetic nuclei; applying a nonselective RF excitation pulse to the paramagnetic nuclei in the selected slice; applying position encoding magnetic field gradients to the paramagnetic nuclei; applying a nonselective RF echo pulse to the paramagnetic nuclei in the selected slice; acquiring an NMR echo signal which is produced by the paramagnetic nuclei in the selected slice; and in which the RF excitation pulse and the RF echo pulse each have a duration less than 500 microseconds.
Claim 2
Independent Claim
121 words
A method of producing an NMR signal from paramagnetic nuclei having a short T 2 relaxation constant, the steps comprising: applying a selective RF saturation pulse in combination with a magnetic field gradient to saturate paramagnetic nuclei on each side of a selected slice of paramagnetic nuclei; applying a nonselective RF excitation pulse to the paramagnetic nuclei in the selected slice; applying position encoding magnetic field gradients to the paramagnetic nuclei; applying a nonselective RF echo pulse to the paramagnetic nuclei in the selected slice; acquiring an NMR echo signal which is produced by the paramagnetic nuclei in the selected slice; and in which the RF excitation pulse and the RF echo pulse each have a duration less than 500 microseconds.
Claim 3
Independent Claim
126 words
A method of producing an NMR signal from paramagnetic nuclei having a short T 2 relaxation constant, the steps comprising: applying a selective RF saturation pulse in combination with a magnetic field gradient to saturate paramagnetic nuclei on each side of a selected slice of paramagnetic nuclei; applying a nonselective RF excitation pulse to the paramagnetic nuclei in the selected slice; applying position encoding magnetic field gradients to the paramagnetic nuclei; applying a nonselective RF echo pulse to the paramagnetic nuclei in the selected slice; acquiring an NMR echo signal which is produced by the paramagnetic nuclei in the selected slice; and in which the RF excitation pulse and the RF echo pulse are each applied to the paramagnetic nuclei as two substantiall orthogonal excitation fields.
Claim 4
Independent Claim
126 words
A method of producing an NMR signal from paramagnetic nuclei having a short T 2 relaxation constant, the steps comprising: applying a selective RF saturation pulse in combination with a magnetic field gradient to saturate paramagnetic nuclei on each side of a selected slice of paramagnetic nuclei; applying a nonselective RF excitation pulse to the paramagnetic nuclei in the selected slice; applying position encoding magnetic field gradients to the paramagnetic nuclei; applying a nonselective RF echo pulse to the paramagnetic nuclei in the selected slice; acquiring an NMR echo signal which is produced by the paramagnetic nuclei in the selected slice; and in which the RF excitation pulse and the RF echo pulse are each applied to the paramagnetic nuclei as two substantiall orthogonal excitation fields.
Claim 5
Independent Claim
110 words
A method of producing an NMR signal from paramagnetic nuclei having a short T 2 relaxation constant, the steps comprising: applying a selective Rf saturation pulse in combination with a magnetic field gradient to saturate paramagnetic nuclei on each side of a selected slice of paramagnetic nuclei; applying a nonselective RF excitation pulse to the paramagnetic nuclei in the selected slice; applying position encoding magnetic field gradients to the paramagnetic nuclei; applying a nonselective RF echo pulse to the paramagnetic nuclei in the selected slice; acquiring an NMR echo signal which is produced by the paramagnetic nuclei in the selected slice; and in which the paramagnetic nuclei are sodium nuclei.
Claim 6
Independent Claim
110 words
A method of producing an NMR signal from paramagnetic nuclei having a short T 2 relaxation constant, the steps comprising: applying a selective Rf saturation pulse in combination with a magnetic field gradient to saturate paramagnetic nuclei on each side of a selected slice of paramagnetic nuclei; applying a nonselective RF excitation pulse to the paramagnetic nuclei in the selected slice; applying position encoding magnetic field gradients to the paramagnetic nuclei; applying a nonselective RF echo pulse to the paramagnetic nuclei in the selected slice; acquiring an NMR echo signal which is produced by the paramagnetic nuclei in the selected slice; and in which the paramagnetic nuclei are sodium nuclei.
Claim 7
Independent Claim
143 words
A method of producing an NMR signal from paramagnetic nuclei having a short T 2 relaxation constant, the steps comprising: applying a selective RF saturation pulse in combination with a magnetic field gradient to saturate paramagnetic nuclei on each side of a selected slice of paramagnetic nuclei; applying a nonselective RF excitation pulse to the paramagnetic nuclei in the selected slice; applying position encoding magnetic field gradients to the paramagnetic nuclei; applying a nonselective RF echo pulse to the paramagnetic nuclei in the selected slice; acquiring an NMR echo signal which is produced by the paramagnetic nuclei in the selected slice; and in which a set of nonselective RF echo pulses are applied to the paramagnetic nuclei in the selected slice and a corresponding set of NMR echo signals are acquired at a plurality of time intervals following the nonselective RF excitation pulse.
Claim 8
Independent Claim
143 words
A method of producing an NMR signal from paramagnetic nuclei having a short T 2 relaxation constant, the steps comprising: applying a selective RF saturation pulse in combination with a magnetic field gradient to saturate paramagnetic nuclei on each side of a selected slice of paramagnetic nuclei; applying a nonselective RF excitation pulse to the paramagnetic nuclei in the selected slice; applying position encoding magnetic field gradients to the paramagnetic nuclei; applying a nonselective RF echo pulse to the paramagnetic nuclei in the selected slice; acquiring an NMR echo signal which is produced by the paramagnetic nuclei in the selected slice; and in which a set of nonselective RF echo pulses are applied to the paramagnetic nuclei in the selected slice and a corresponding set of NMR echo signals are acquired at a plurality of time intervals following the nonselective RF excitation pulse.
Claim 9
Dependent Claim
29 words
The method as recited in claim 4 in which a trim gradient pulse is applied after the application of each of the second and subsequent nonselective RF echo pulses.
Claim 10
Independent Claim
122 words
A method of producing an NMR signal from paramagnetic nuclei having a short T 2 relaxation constant, the steps comprising: applying a selective RF saturation pulse in combination with a magnetic field gradient to saturate paramagnetic nuclei on each side of a selected slice of paramagnetic nuclei; applying a nonselective RF excitation pulse to the paramagnetic nuclei in the selected slice; applying position encoding magnetic field gradients to the paramagnetic nuclei; applying a magnetic field gradient which causes the paramagnetic nuclei in the selected slice to rephase and emit an NMR echo signal; acquiring the NMR echo signal which is produced by the paramagnetic nuclei in the presence of said magnetic field gradient; and in which the paramagnetic nuclei are sodium nuclei.
Claim 11
Independent Claim
122 words
A method of producing an NMR signal from paramagnetic nuclei having a short T 2 relaxation constant, the steps comprising: applying a selective RF saturation pulse in combination with a magnetic field gradient to saturate paramagnetic nuclei on each side of a selected slice of paramagnetic nuclei; applying a nonselective RF excitation pulse to the paramagnetic nuclei in the selected slice; applying position encoding magnetic field gradients to the paramagnetic nuclei; applying a magnetic field gradient which causes the paramagnetic nuclei in the selected slice to rephase and emit an NMR echo signal; acquiring the NMR echo signal which is produced by the paramagnetic nuclei in the presence of said magnetic field gradient; and in which the paramagnetic nuclei are sodium nuclei.
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) | 1992-02-07 | 1992-08-08 | 1993-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-07 | 1996-08-08 | 1997-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-07 | 2000-08-08 | 2001-02-07 | $7700.00 | Window Closed / Lapsed |