EP0127480A2
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EP
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Simultaneous NMR imaging system
Assignee: Individual
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Filing: 1984-05-29
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Granted: —
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Expires: 2004-05-29
Abstract
Abstract The nuclei in a volume are imaged using one or more time-varying gradient fields. The resultant signals are heterodyned using a signal having a related time-varying component. Equivalently,the spectrum ofthe resultantsignal is convolved with the spectrum of the heterodyne signal. Following integration, depending on the amplitude of the time-varying component of the heterodyne signal, any point in the volume can be studied from the same received signal.
Inventors
- 👤 Albert Macovski
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 01:40
CPC Classifications
G; G01; G01N; G01N24/00; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/4818; G01R33/482; G01R33/54; G01R33/56; G01R33/28; G01R33/32; G01R33/36; G01R33/3621
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
75 words
In a method for measuring the NMR activity of points in a volume the steps of: exciting the volume with an rf excitation signal; receiving signals emitted from the volume in the presence of a time-varying magnetic field gradients; and processing the received signal to derive information about the NMR activity of points in the volume using a plurality of components of the frequency spectrum of the received signal to derive information about each point.
Claim 2
Dependent Claim
75 words
In a method for measuring the NMR activity of points in a volume the steps of: exciting the volume with an rf excitation signal; receiving signals emitted from the volume in the presence of a time-varying magnetic field gradients; and processing the received signal to derive information about the NMR activity of points in the volume using a plurality of components of the frequency spectrum of the received signal to derive information about each point.
Claim 3
Dependent Claim
49 words
The method as described in claim 1 wherein the step of processing includes the steps of: multiplying the received signal by a heterodyne signal phase modulated by a function of the time-varying magnetic field gradient to provide a mixed signal; demodulating the mixed signal; and integrating the demodulated signal.
Claim 4
Dependent Claim
55 words
The method as described in claim 1 wherein the step of processing includes the steps of: convolving the frequency spectrum of the received signal with the frequency spectrum of a sinusoidal signal. phase-modulated by a function of the time-varying magnetic field gradient; and measuring the amplitude of the carrier frequency component of the convolved signal.
Claim 5
Dependent Claim
67 words
The method as described in claim 1 wherein the step of processing includes the steps of: weighting each significant component of the frequency spectrum of the received signal by a predetermined set of weights representing the sideband amplitudes of a sinusoid phase modulated by a function of the time-varying gradient modulation signal which determine the position of the point in the volume; and summing the weighted components.
Claim 6
Dependent Claim
57 words
The method as described in claim 2 where the gradient signal is periodic and including the step of demodulating sidebands of the mixed signal separated from the carrier by multiples of the gradient modulation frequency and adding weighted amounts of the demodulated sideband signals to the integrated signal whereby a more localized spatial response function is derived.
Claim 7
Dependent Claim
67 words
The method as described in claim 3 where the gradient signal is periodic and including the step of measuring the amplitude of sidebands of the carrier frequency of the convolved signal separated from the carrier by multiples of the gradient modulation frequency and adding weighted mounts of the sideband amplitudes to the amplitude of the carrier frequency component whereby a more localized spatial response function is derived.
Claim 8
Dependent Claim
56 words
The method as described in claim 4 where the gradient signal is periodic and including the steps of similarly weighting the frequency spectrum of the received signal using a translated version of the predetermined set of weights and combining the translated weighted spectrum with the weighted spectrum whereby a more localized spatial response function is derived.
Claim 9
Dependent Claim
50 words
The method as described in claim 1 wherein the step of exciting the volume includes the step of exciting a planar section of the volume and the step of receiving signals includes the step of receiving signals in the presence of time- varying field gradients parallel to the planar section.
Claim 10
Dependent Claim
49 words
The method as described in claim 1 wherein the step of exciting the volume includes the step of simultaneously exciting the volume of interest and the step of receiving signals includes the step of receiving signals in the presence of three time-varying field gradients which are substantially mutually perpendicular.
Claim 11
Dependent Claim
42 words
The method as described in claim 1 wherein the step of processing the received signal includes the step of decomposing the signal into its fine frequency components to derive the NMR spectrum of the material being studied at points in the volume.
Claim 12
Dependent Claim
24 words
The method as described in claim 1 including the step of processing the received signal to derive information about moving material in the volume.
Claim 13
Dependent Claim
26 words
The method as described in claim 1 including the step of processing the received signal to form projection images of the NMR activity of the volume.
Claim 14
Dependent Claim
67 words
Apparatus for measuring the NMR activity of a volume comprising: means for exciting the volume with an rf excitation field; means for receiving signals emitted from the volume in the presence of time-varying gradient fields; and means for processing the received signal to derive information about the NMR activity of points in the volume using a plurality of components of the frequency spectrum of the received signal.
Claim 15
Dependent Claim
67 words
Apparatus for measuring the NMR activity of a volume comprising: means for exciting the volume with an rf excitation field; means for receiving signals emitted from the volume in the presence of time-varying gradient fields; and means for processing the received signal to derive information about the NMR activity of points in the volume using a plurality of components of the frequency spectrum of the received signal.
Claim 16
Dependent Claim
53 words
Apparatus as described in claim 13 wherein the processing means includes: means for multiplying the received signal by a heterodyne signal which is phase modulated by a function of the time-varying magnetic field gradient signal to provide a mixed signal; means for demodulating the mixed signal; and means for integrating the mixed signal.
Claim 17
Dependent Claim
56 words
Apparatus as described in claim 14 where the gradient modulation signal is periodic and including means for demodulating sidebands of the mixed signal separated from the carrier by multiples of the gradient modulation frequency and adding weighted amounts of the demodulated sideband signals to the integrated signal whereby a more localized spatial response function is derived.
Claim 18
Dependent Claim
55 words
Apparatus as described in claim 13 wherein the processing means includes: means for convolving the frequency spectrum of the received signal with the frequency spectrum of a sinusoidal signal phase-modulated by a function of the time-varying magnetic field gradient signal; and means for measuring the amplitude of the carrier frequency component of the convolved signal.
Claim 19
Dependent Claim
68 words
1 7.. Apparatus as described in claim 16 where the gradient modulation signal is periodic and including means for measuring the amplitude of sidebands of the carrier frequency of the convolved signal separated from the carrier by multiples of the gradient modulation frequency and adding weighted amounts of these sideband amplitudes to the amplitude of the carrier frequency component whereby a more localized spatial response function is derived.
Claim 20
Dependent Claim
66 words
Apparatus as described in claim 13 wherein the processing means includes: means for weighting each significant component of the frequency spectrum of the received signal using a predetermined set of weights representing the sideband amplitudes of a sinusoid phase modulated by a function of the gradient modulation signal which determines the position of the point in the volume; and means for summing the weighted spectral components.
References Cited (Backward Citations)
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