US5235276A
Expired / Lapsed
US
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Rapid pulse magnetic resonance analysis
Assignee: Individual
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Filing: 1991-08-13
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Granted: 1993-08-10
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Expires: 2011-08-13
Abstract
Abstract The principles of nuclear magnetic resonance are employed to determine material properties of test subjects such as the constituent ratios of component elements making up the test subject and the rate of fluid change taking place in the test subject, in which analysis a plurality of magnetic resonance radiations from the test subject are generated by a plurality of series of 90 degree pulses of alternating magnetic field having different pause periods between adjacent pulses, and each measured value of the intensity of the plurality of magnetic resonance radiations is substituted into a mathematical relationship relating the intensity of the magnetic resonance radiation to a plurality of sources thereof respectively associated with the material properties, which relationship provides a set of simultaneous algebraic equations, that is solved to obtain the numerical values of the material properties.
Inventors
- 👤 Hyok S. Lew
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:14
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/54; G01R33/56; G01R33/563
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
326 words
A method for determining solid-fluid state properties of a test mass forming a portion of a test subject, comprising in combination: a) placing the test subject in a substantially constant magnetic field wherein the test mass is exposed to an alternating magnetic field generally perpendicular to the constant magnetic field and oscillating at a magnetic resonance frequency appropriate to a combination of the strength of the constant magnetic field existing in a region occupied by the test mass and the gyromagnetic ratio of an atomic species included in the test mass that produces magnetic resonance effect, said alternating magnetic field altering ordered orientations of nuclei magnets belonging to said atomic species included in the test mass without significantly altering ordered orientations of nuclei magnets belonging to said atomic species located outside the test mass; b) identifying number of the solid-fluid state properties to be determined; c) generating a plurality of magnetic resonance radiations from the test mass by exposing the test mass to a plurality of series of pulses of the alternating magnetic field having different values of pause period between adjacent pulses, and measuring intensities of each of the plurality of magnetic resonance radiations, wherein number of said plurality of magnetic resonance radiations is at least equal to number of the solid-fluid state properties to be determined; d) establishing a mathematical relationship defining magnetic resonance radiation from the test mass as a sum of a plurality of magnetic resonance radiations respectively emitted in association with the solid-fluid state properties to be determined; e) constructing a set of simultaneous algebraic equations in number at least equal to the number of the solid-fluid state properties to be determined by substituting the measured intensities of the plurality of magnetic resonance radiations from the test mass into said mathematical relationship; and f) determining numerical values of the solid-fluid state properties to be determined by solving the set of simultaneous algebraic equations for the solid-fluid state properties to be determined.
Claim 2
Independent Claim
326 words
A method for determining solid-fluid state properties of a test mass forming a portion of a test subject, comprising in combination: a) placing the test subject in a substantially constant magnetic field wherein the test mass is exposed to an alternating magnetic field generally perpendicular to the constant magnetic field and oscillating at a magnetic resonance frequency appropriate to a combination of the strength of the constant magnetic field existing in a region occupied by the test mass and the gyromagnetic ratio of an atomic species included in the test mass that produces magnetic resonance effect, said alternating magnetic field altering ordered orientations of nuclei magnets belonging to said atomic species included in the test mass without significantly altering ordered orientations of nuclei magnets belonging to said atomic species located outside the test mass; b) identifying number of the solid-fluid state properties to be determined; c) generating a plurality of magnetic resonance radiations from the test mass by exposing the test mass to a plurality of series of pulses of the alternating magnetic field having different values of pause period between adjacent pulses, and measuring intensities of each of the plurality of magnetic resonance radiations, wherein number of said plurality of magnetic resonance radiations is at least equal to number of the solid-fluid state properties to be determined; d) establishing a mathematical relationship defining magnetic resonance radiation from the test mass as a sum of a plurality of magnetic resonance radiations respectively emitted in association with the solid-fluid state properties to be determined; e) constructing a set of simultaneous algebraic equations in number at least equal to the number of the solid-fluid state properties to be determined by substituting the measured intensities of the plurality of magnetic resonance radiations from the test mass into said mathematical relationship; and f) determining numerical values of the solid-fluid state properties to be determined by solving the set of simultaneous algebraic equations for the solid-fluid state properties to be determined.
Claim 3
Dependent Claim
76 words
A method as set forth in claim 1 wherein carrying out said method for determining the solid-fluid state properties of the test mass for a plurality of test masses forming a set of matrix subdivisions of the test subject, and constructing an image representing a spatial distribution of at least one of the solid-fluid state properties in the test subject by assembling the numerical values of the solid-fluid state properties of the plurality of test masses.
Claim 4
Dependent Claim
171 words
A method as set forth in claim 1 wherein the solid-fluid state properties to be determined comprises constituent ratios of component elements of n different species making up the test mass, and said set of simultaneous algebraic equations is of the following form: ##EQU10## where V j is the measured intensity of jth magnetic resonance radiation of said plurality of magnetic resonance radiations from the test mass, that is generated by one of the plurality of series of pulses of the alternating magnetic field with pause period equal to τj, C i is an empirically determined physical coefficient representing effectiveness of ith component element in emitting magnetic resonance radiation, M i is mass of ith component element, T i is an empirically determined relaxation time characterizing speed of magnetization of ith component element, and f stands for an empirically determined monotonically decaying mathematical function; wherein the set of simultaneous algebraic equation is solved for M i 's as a measure of constituent ratios of component elements making up the test mass.
Claim 5
Dependent Claim
23 words
A method as set forth in claim 3 wherein the monotonically decaying mathematical function f is equal to an inverse of exponential function.
Claim 6
Dependent Claim
77 words
A method as set forth in claim 3 wherein carrying out said method for determining the constituent ratios of component elements making up the test mass for a plurality of test masses forming a set of matrix subdivisions of the test subject, and constructing an image representing a spatial distribution of at least one of the component elements in the test subject by assembling the numerical values of the constituent ratios of the plurality of test masses.
Claim 7
Dependent Claim
251 words
A method as set forth in claim 1 wherein the solid-fluid state properties to be determined comprises intensities of magnetic resonance radiations from stationary component elements making up the test mass and rate of fluid change taking place in the test mass, and said set of simultaneous algebraic equations is of the following form: ##EQU11## where V(τ i ) is the measured of ith magnetic resonance radiation of said plurality of magnetic resonance radiations from the test mass, that is generated by one of the plurality of series of pulses of the alternating magnetic field with pause period equal to τ i , C S and C F are empirically determined physical coefficients respectively representing effectiveness of solid and fluid component elements making up the test mass in emitting magnetic resonance radiation, M S and M F are respectively masses of stationary solid and stationary fluid component elements in the test mass, M is the rate of fluid mass change taking place in the test mass, T S and T F are respectively empirically determined relaxation times characterizing speed of magnetization of the solid and fluid component elements, L is the characteristic linear dimension of the test mass, and f stands for an empirically determined monotonically decaying mathematical function; wherein the set of simultaneous algebraic equations is solved for (C S M S ), (C F M F ) and M and the rate of fluid change taking place in the test mass is determined from the numerical value of M.
Claim 8
Dependent Claim
23 words
A method as set forth in claim 6 wherein the monotonically decaying mathematical function f is equal to an inverse of exponential function.
Claim 9
Dependent Claim
122 words
A method as set forth in claim 6 wherein carrying out said method for determining the intensities of magnetic resonance radiations from stationary component elements making up the test mass and rate of fluid change taking place in the test mass for a plurality of test masses forming a set of matrix subdivisions of the test subject, and constructing an image representing a spatial distribution of at least one of the intensities of magnetic resonance radiations from stationary component elements and the rate of fluid change in the test subject by assembling the numerical values of said one of the intensities of magnetic resonance radiations from stationary component elements and the rate of fluid change in the plurality of the test masses.
Claim 10
Independent Claim
268 words
A method for determining rate of fluid change taking place in a test mass forming a portion of a test subject, comprising in combination: a) placing the test subject in a substantially constant magnetic field wherein the test mass is exposed to an alternating magnetic field generally perpendicular to the constant magnetic field and oscillating at a magnetic resonance frequency appropriate to a combination of the strength of the constant magnetic field existing in a region occupied by the test mass and the gyromagnetic ratio of an automatic species included in the test mass that produces magnetic resonance effect, said alternating magnetic field altering ordered orientations of nuclei magnets belonging to said atomic species included in the test mass without significantly altering ordered orientations of nuclei magnets belonging to said atomic species located outside the test mass; b) generating at least one magnetic resonance radiation from the test mass by exposing the test mass to a series of pulses of the alternating magnetic field with a pause period between adjacent pulses, said pause period having such a length that a significant amount of fluid change takes place in the duration of the pause period, and measuring intensity of the magnetic resonance radiation from the test mass; c) determining intensity of magnetic resonance radiation from stationary solid and stationary fluid component elements in the test mass empirically; and d) determining rate of fluid change taking place in the test mass from difference in intensity between the magnetic resonance radiation from the test mass and the magnetic resonance radiation from the stationary solid and stationary fluid in the test mass.
Claim 11
Independent Claim
268 words
A method for determining rate of fluid change taking place in a test mass forming a portion of a test subject, comprising in combination: a) placing the test subject in a substantially constant magnetic field wherein the test mass is exposed to an alternating magnetic field generally perpendicular to the constant magnetic field and oscillating at a magnetic resonance frequency appropriate to a combination of the strength of the constant magnetic field existing in a region occupied by the test mass and the gyromagnetic ratio of an automatic species included in the test mass that produces magnetic resonance effect, said alternating magnetic field altering ordered orientations of nuclei magnets belonging to said atomic species included in the test mass without significantly altering ordered orientations of nuclei magnets belonging to said atomic species located outside the test mass; b) generating at least one magnetic resonance radiation from the test mass by exposing the test mass to a series of pulses of the alternating magnetic field with a pause period between adjacent pulses, said pause period having such a length that a significant amount of fluid change takes place in the duration of the pause period, and measuring intensity of the magnetic resonance radiation from the test mass; c) determining intensity of magnetic resonance radiation from stationary solid and stationary fluid component elements in the test mass empirically; and d) determining rate of fluid change taking place in the test mass from difference in intensity between the magnetic resonance radiation from the test mass and the magnetic resonance radiation from the stationary solid and stationary fluid in the test mass.
Claim 12
Dependent Claim
59 words
A method as set forth in claim 9 wherein the pause period in the series of pulses of the alternating magnetic field is set to a value much smaller than spin-lattice relaxation time of fluid component element in the test mass, whereby the stationary fluid component element in the test mass emits magnetic resonance radiation of negligibly small intensity.
Claim 13
Dependent Claim
33 words
A method as set forth in claim 9 wherein intensity of magnetic resonance radiation from the stationary solid and stationary fluid component elements in the test mass is heuristically set equal to zero.
References Cited (Backward Citations)
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