EP0123200A2
Expired / Lapsed
EP
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Method to eliminate the effects of magnetic field inhomogeneities in NMR imaging
Assignee: Yeda Research and Development Co Ltd
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Filing: 1984-04-10
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Granted: —
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Expires: 2004-04-10
Abstract
Abstract NMR imaging apparatus comprising apparatus for applying a linear magnetic field gradientto a sample, apparatus for varying the magnetic field gradient in a predetermined manner, apparatus for obtaining an NMR signal based on the linear magnetic field gradient, apparatus for storing the NMR signal, apparatus for reconstructing an NMR image from the stored NMR signal, and display apparatus for displaying the reconstructed NMR image, and wherein the apparatus for obtaining an NMR signal includes apparatus for obtaining the NMR signal at times when cancellation of the signal component dependent on magnetic field inhomogeneities occurs. There is also provided a technique for NMR imaging using the above apparatus.
Inventors
- 👤 Peter Bendel
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 12:45
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/4818; G01R33/482; G01R33/54; G01R33/56; G01R33/565; G01R33/56563; G01R33/561; G01R33/5615; G01R33/5617
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
105 words
NMR imaging apparatus comprising: means for applying a linear magnetic field gradient to a sample; means for varying the magnetic field gradient in a predetermined manner; means for providing r. f. excitation pulses to said sample; means for obtaining an NMR signal based on the linear magnetic field gradient; means for storing the NMR signal; means for reconstructing an NMR image from the stored NMR signal; and display means for displaying the reconstructed NMR image, and wherein the means for obtaining an NMR signal includes means for obtaining the NMR signal at times when cancellation of the signal component dependent on magnetic field inhomogeneities occurs.
Claim 2
Dependent Claim
105 words
NMR imaging apparatus comprising: means for applying a linear magnetic field gradient to a sample; means for varying the magnetic field gradient in a predetermined manner; means for providing r. f. excitation pulses to said sample; means for obtaining an NMR signal based on the linear magnetic field gradient; means for storing the NMR signal; means for reconstructing an NMR image from the stored NMR signal; and display means for displaying the reconstructed NMR image, and wherein the means for obtaining an NMR signal includes means for obtaining the NMR signal at times when cancellation of the signal component dependent on magnetic field inhomogeneities occurs.
Claim 3
Dependent Claim
53 words
Apparatus according to claim 1 and wherein said means for varying said magnetic field gradient shifts the sign of said gradient at times t =(2n - 1)τ where n is a non-zero integer and wherein .said means for obtaining the NMR signal is operative to obtain said signal at times t = 2nτ.
Claim 4
Dependent Claim
25 words
Apparatus according to claim 2 and wherein said means for obtaining the NMR signal is operative to obtain said signal at times t = 4nτ.
Claim 5
Dependent Claim
46 words
Apparatus according to claim 1 and wherein said means for providing excitation signal pulses to said sample is operative to provide excitation signal pulses whose onset corresponds with the change in sign of the magnetic field gradient provided by said means for varying the magnetic field.
Claim 6
Dependent Claim
95 words
A technique for NMR imaging comprising the steps of: applying a linear magnetic field gradient to a sample; varying the magnetic field gradient in a predetermined manner; applying r._f. excitation pulses to said sample; obtaining an NMR signal based on the linear magnetic field gradient; storing the NMR signal; reconstructing an NMR image from the stored NMR signal; and displaying the reconstructed NMR image, and wherein the step of obtaining an NMR signal includes the step of obtaining the NMR signal at times when cancellation of the signal component dependent on magnetic field inhomogeneities occurs.
Claim 7
Dependent Claim
95 words
A technique for NMR imaging comprising the steps of: applying a linear magnetic field gradient to a sample; varying the magnetic field gradient in a predetermined manner; applying r._f. excitation pulses to said sample; obtaining an NMR signal based on the linear magnetic field gradient; storing the NMR signal; reconstructing an NMR image from the stored NMR signal; and displaying the reconstructed NMR image, and wherein the step of obtaining an NMR signal includes the step of obtaining the NMR signal at times when cancellation of the signal component dependent on magnetic field inhomogeneities occurs.
Claim 8
Dependent Claim
62 words
A technique according to claim 6 and wherein said step of varying the magnetic field gradient includes the step of shifting the sign of the magnetic field gradient at times t =(2n - 1) τ where n is a non-zero integer and wherein said step of obtaining the NMR signal includes the steps of obtaining said signal at times t = 2nτ.
Claim 9
Dependent Claim
27 words
A technique according to claim 7 and wherein said step of obtaining the NMR signal includes the steps of obtaining said signal at times t = 4nτ.
Claim 10
Dependent Claim
49 words
A technique according to claim 5 and wherein said step of applying r. f.excitation signal pulses to said sample includes the steps of providing excitation signal pulses whose onset corresponds with the change in sign of the magnetic field gradient provided by said means for varying the magnetic field.
References Cited (Backward Citations)
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