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US4604579A
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Method and apparatus for enhanced T1 NMR measurements using repetition intervals TR related to one another by integer multiples
Assignee: University of California
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Filing: 1983-07-21
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Granted: 1986-08-05
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Expires: 2003-07-21
Abstract
Abstract An analytic closed solution for the spin-lattice relaxation time T1 is provided in terms of the repetition interval time TR and the differing NMR signal response intensities I 1 and I 2 obtained when using different repetition intervals TR 1 and TR 2 which are related to one another by integer multipliers. The result is a method and apparatus which directly and non-iteratively generate a spin-lattice relaxation time signal value T1 for each voxel within a selected region of an object under test so as to quickly, economically and accurately produce a T1 image of nutated nuclei within the region.
Inventors
- 👤 Clifford R. Cannon
- 👤 Douglas A. Ortendahl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:25
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/50
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
99 words
A method of generating a spin-lattice relaxation time value T1 for NMR-excited nuclei, said method comprising the steps of: measuring an NMR signal intensity value I 1 for said nuclei using a first TR NMR time; measuring an NMR signal intensity value I 2 for said nuclei using a second TR NMR time where said first and second TR times are related to one another by an integer multiplier greater than one; and directly generating a spin-lattice relaxation time T1 for said nuclei from said measured I 1 and I 2 signal intensity values and said first TR time.
Claim 2
Independent Claim
99 words
A method of generating a spin-lattice relaxation time value T1 for NMR-excited nuclei, said method comprising the steps of: measuring an NMR signal intensity value I 1 for said nuclei using a first TR NMR time; measuring an NMR signal intensity value I 2 for said nuclei using a second TR NMR time where said first and second TR times are related to one another by an integer multiplier greater than one; and directly generating a spin-lattice relaxation time T1 for said nuclei from said measured I 1 and I 2 signal intensity values and said first TR time.
Claim 3
Dependent Claim
36 words
A method as in claim 1 wherein said second TR time is twice said first TR time and wherein said spin-lattice relaxation time T1 is generated in accordance with the function T1=TR/[1n(I 2 /I 1 -1)].
Claim 4
Dependent Claim
33 words
A method as in claim 1 wherein said second TR time is three times said first TR time and wherein said spin-lattice relaxation time T1 is generated in accordance with the function ##EQU12##
Claim 5
Dependent Claim
37 words
A method as in claim 1 wherein said second TR time is four times said first TR time and wherein said spin-lattice relaxation time T1 is generated in accordance with the function T1=-TR 1 /1n(A-B-1)/3) where ##EQU13##
Claim 6
Dependent Claim
67 words
A method as in claim 1 wherein each of said measuring steps comprises: (a) exciting said nuclei with a 90° NMR nutation pulse; (b) subsequently exciting said nuclei with a 180° NMR nutation pulse; (c) subsequently detecting at least one NMR spin echo signal emanating from said nuclei; and (d) repeating steps (a)-(c) at a repetition interval related to the TR time for each said measuring step.
Claim 7
Dependent Claim
36 words
A method as in claim 5 wherein said second TR time is twice said first TR time and wherein said spin-lattice relaxation time T1 is generated in accordance with the function T1=TR/[1n(I 2 /I 1 -1)].
Claim 8
Dependent Claim
33 words
A method as in claim 5 wherein said second TR time is three times said first TR time and wherein said spin-lattice relaxation time T1 is generated in accordance with the function ##EQU14##
Claim 9
Dependent Claim
37 words
A method as in claim 5 wherein said second TR time is four times said first TR time and wherein said spin-lattice relaxation time T1 is generated in accordance with the function T1=-TR 1 /1n((A-B-1)/3) where ##EQU15##
Claim 10
Dependent Claim
39 words
A method as in claim 1, 2, 3, 4, 5, 6, 7 or 8 wherein said generating step is performed in a digital computer by processing digital electrical signals representing said I 1 , I 2 and TR values.
Claim 11
Independent Claim
131 words
A method of generating an NMR image of the T1 spin-lattice relaxation times for NMR-excited nuclei within a selected region of an object, said method comprising the steps of: acquiring an NMR signal intensity value I 1 for each voxel within said selected region using first TE and first TR NMR timing signal values; acquiring an NMR signal intensity value I 2 for each voxel within said selected region using a second TR NMR timing signal value where said first and second TR timing signal values are related to one another by an integer multiplier greater than one; and directly and non-iteratively generating a spin-lattice relaxation time signal value T 1 for each voxel within said selected region from said I 1 , I 2 and said first TR signal values.
Claim 12
Independent Claim
131 words
A method of generating an NMR image of the T1 spin-lattice relaxation times for NMR-excited nuclei within a selected region of an object, said method comprising the steps of: acquiring an NMR signal intensity value I 1 for each voxel within said selected region using first TE and first TR NMR timing signal values; acquiring an NMR signal intensity value I 2 for each voxel within said selected region using a second TR NMR timing signal value where said first and second TR timing signal values are related to one another by an integer multiplier greater than one; and directly and non-iteratively generating a spin-lattice relaxation time signal value T 1 for each voxel within said selected region from said I 1 , I 2 and said first TR signal values.
Claim 13
Dependent Claim
45 words
A method as in claim 10 wherein said second TR 2 timing signal is two times said first TR timing signal value and wherein said spin-lattice relaxation time signal value T1 is generated in accordance with the function T1=TR 1 /[1n(I 2 /I 1 -1)].
Claim 14
Dependent Claim
26 words
A method as in claim 10 wherein said acquired NMR signals are spin echos emanating from nuclei that have been successively nutated by 90° and 180°.
Claim 15
Dependent Claim
43 words
A method as in claim 12 wherein said second TR timing signal is two times said first TR timing signal value and wherein said spin-lattice relaxation time signal value T 1 is generated in accordance with the function T1=TR/[1n(I 2 /I 1 -1)].
Claim 16
Dependent Claim
35 words
A method as in claim 10, 11, 12 or 13 wherein said generating step is performed in a digital computer by processing digital electrical signals representing I 1 , I 2 and TR 1 values.
Claim 17
Dependent Claim
100 words
Apparatus for generating a spin-lattice relaxation time value T1 for NMR-excited nuclei, said apparatus comprising: means for measuring an NMR signal intensity value I 1 for said nuclei using a first TR NMR time; means for measuring an NMR signal intensity value I 2 for said nuclei using a second TR NMR time where said first and second TR times are related to one another by an integer multiplier greater than one; and means for directly generating a spin-lattice relaxation time T1 for said nuclei from said measured I 1 and I 2 signal intensity values and said TR time.
Claim 18
Dependent Claim
100 words
Apparatus for generating a spin-lattice relaxation time value T1 for NMR-excited nuclei, said apparatus comprising: means for measuring an NMR signal intensity value I 1 for said nuclei using a first TR NMR time; means for measuring an NMR signal intensity value I 2 for said nuclei using a second TR NMR time where said first and second TR times are related to one another by an integer multiplier greater than one; and means for directly generating a spin-lattice relaxation time T1 for said nuclei from said measured I 1 and I 2 signal intensity values and said TR time.
Claim 19
Dependent Claim
45 words
Apparatus as in claim 15 including means for causing said second TR time to be twice said first TR time and wherein said means for generating includes means for generating said spin-lattice relaxation time T1 in accordance with the function T1=TR/[1n(I 2 /I 1 -1)].
Claim 20
Dependent Claim
75 words
Apparatus as in claim 15 wherein each of said means for measuring comprises: (a) means for exciting said nuclei with a 90° NMR nutation pulse; (b) means for subsequently exciting said nuclei with a 180° NMR nutation pulse; (c) means for subsequently detecting at least one NMR spin echo signal emanating from said nuclei; and (d) means for repetitively operating said means (a)-(c) at a repetition interval related to the TR time for each measurement.
Claim 21
Dependent Claim
45 words
Apparatus as in claim 17 including means for causing said second TR time to be twice said first TR time and wherein said means for generating includes means for generating said spin-lattice relaxation time T1 in accordance with the function T1=TR/[1n(I 2 /I 1 -1)].
Claim 22
Dependent Claim
33 words
Apparatus as in claim 15, 16, 17 or 18 wherein said means for generating comprises a digital computer for processing digital electrical signals representing said I 1 , I 2 and TR values.
Claim 23
Dependent Claim
132 words
Apparatus for generating an NMR image of the T1 spin-lattice relaxation times for NMR-excited nuclei within a selected region of an object, said apparatus comprising: means for acquiring an NMR signal intensity value I 1 for each voxel within said selected region using first TE and first TR NMR timing signal values; means for acquiring an NMR signal intensity value I 2 for each voxel within said selected region using a second TR NMR timing signal value where said first and second TR timing signal values are related to one another by an integer multiplier greater than one; and means for directly and non-iteratively generating a spin-lattice relaxation time signal value T1 for each voxel within said selected region from said I 1 , I 2 and said first TR signal values.
Claim 24
Dependent Claim
132 words
Apparatus for generating an NMR image of the T1 spin-lattice relaxation times for NMR-excited nuclei within a selected region of an object, said apparatus comprising: means for acquiring an NMR signal intensity value I 1 for each voxel within said selected region using first TE and first TR NMR timing signal values; means for acquiring an NMR signal intensity value I 2 for each voxel within said selected region using a second TR NMR timing signal value where said first and second TR timing signal values are related to one another by an integer multiplier greater than one; and means for directly and non-iteratively generating a spin-lattice relaxation time signal value T1 for each voxel within said selected region from said I 1 , I 2 and said first TR signal values.
Claim 25
Dependent Claim
54 words
Apparatus as in claim 20 including means for causing said second TR 2 timing signal to be two times said first TR timing signal value and wherein said means for generating including means for generating said spin-lattice relaxation time signal value T1 in accordance with the function T1=TR 1 /[1n(I 2 /I 1 -1)].
Claim 26
Dependent Claim
28 words
Apparatus as in claim 20 wherein said means for acquiring includes means for acquiring spin echos emanating from nuclei that have been successively nutated by 90° and 180°.
Claim 27
Dependent Claim
51 words
Apparatus as in claim 22 including means for causing said second TR timing signal to be two times said first TR timing signal value and wherein said means for generating includes means for generating said spin-lattice relaxation time signal value T1 in accordance with the function T1=TR/[1n(I 2 /I 1 -1)].
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) | 1989-08-04 | 1990-02-03 | 1990-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-04 | 1994-02-03 | 1994-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-04 | 1998-02-03 | 1998-08-05 | $7700.00 | Window Closed / Lapsed |