EP0112663A2
Expired / Lapsed
EP
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Nuclear magnetic resonance methods and apparatus
Assignee: Philips Design Ltd
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Filing: 1983-11-30
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Granted: —
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Expires: 2003-11-30
Abstract
Abstract A multi-slice method of NMR imaging wherein a number of discrete slices S 1 , S 2 , S 3 , S 4 are excited simultaneously by using the usual field gradient Gz but an r. f. pulse B, which is a mix of a number of pulses of different discrete frequencies, f 1 , f 2 , f 3 , f 4 , and recovering data in the presence of an alternating gradient G 2 z in the same direction as used to establish the slices such that discrete spin echo signals of different frequency occur for each slice. Apparatus for use in the method is also disclosed.
Inventors
- 👤 Ian Robert Young
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 11:05
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/483; G01R33/4833; G01R33/4835
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
195 words
A method of obtaining a representation of the spatial distribution in a plurality of sutotantially parallel slices (S 1 , S 2 , S 3 , S 4 ) of a body of a quantity relating to nuclear magnetic resonance characterised in that it includes: applying a uniform magnetic field (Bo) to said body; imposing a first gradient (Gz)- on said field in a chosen direction; applying a plurality of r.f. field pulses each within a different discrete frequency band (fl, f2, f3, f4) so as to excite nuclear magnetic resonance preferentially in a plurality of spaced parallel planar slices (S 1 , S 2 , S 3 , S 4 ) of said body whose planes lie perpendicular to said chosen direction; removing said first gradient (Gz), and subsequently applying a second gradient (G 2 z) on said field in said chosen direction, the direction of said second gradient being periodically reversed; detecting nuclear magnetic resonance signals occurring while said second (G 2 z) gradient is imposed; and processing said signals to derive data relating to each of said plurality of slices (S 1 , S 2 , S 3 , S 4 ).
Claim 2
Independent Claim
195 words
A method of obtaining a representation of the spatial distribution in a plurality of sutotantially parallel slices (S 1 , S 2 , S 3 , S 4 ) of a body of a quantity relating to nuclear magnetic resonance characterised in that it includes: applying a uniform magnetic field (Bo) to said body; imposing a first gradient (Gz)- on said field in a chosen direction; applying a plurality of r.f. field pulses each within a different discrete frequency band (fl, f2, f3, f4) so as to excite nuclear magnetic resonance preferentially in a plurality of spaced parallel planar slices (S 1 , S 2 , S 3 , S 4 ) of said body whose planes lie perpendicular to said chosen direction; removing said first gradient (Gz), and subsequently applying a second gradient (G 2 z) on said field in said chosen direction, the direction of said second gradient being periodically reversed; detecting nuclear magnetic resonance signals occurring while said second (G 2 z) gradient is imposed; and processing said signals to derive data relating to each of said plurality of slices (S 1 , S 2 , S 3 , S 4 ).
Claim 3
Dependent Claim
40 words
A method according to Claim 1 in which at least one further gradient (G R ) parallel to the planes of said slices is imposed on said field (Bo) so as to disperse the resonance within each of said slices.
Claim 4
Independent Claim
144 words
An apparatus arranged to obtain a representation of the spatial distribution in a plurality of substantially parallel slices of a body of a quantity relating to nuclear magnetic resonance characterised in that it includes: means (1) arranged to apply a uniform magnetic field; means (7) arranged to impose a first gradient on said field in a chosen direction; means (9, 19, 27, 45, 47) arranged to apply a plurality of r.f. field pulses each within a different discrete frequency band; means (7) arranged to remove said first gradient, and subsequently apply a second gradient on said field in said chosen direction, the direction of said second gradient being periodically reversed; means (9) arranged to detect nuclear magnetic resonance occurring while said second gradient is imposed; and means (37) arranged to process said signals to derive data relating to each of said plurality of slices.
Claim 5
Independent Claim
144 words
An apparatus arranged to obtain a representation of the spatial distribution in a plurality of substantially parallel slices of a body of a quantity relating to nuclear magnetic resonance characterised in that it includes: means (1) arranged to apply a uniform magnetic field; means (7) arranged to impose a first gradient on said field in a chosen direction; means (9, 19, 27, 45, 47) arranged to apply a plurality of r.f. field pulses each within a different discrete frequency band; means (7) arranged to remove said first gradient, and subsequently apply a second gradient on said field in said chosen direction, the direction of said second gradient being periodically reversed; means (9) arranged to detect nuclear magnetic resonance occurring while said second gradient is imposed; and means (37) arranged to process said signals to derive data relating to each of said plurality of slices.
Claim 6
Dependent Claim
28 words
An apparatus according to Claim 4 including means (3, 5) arranged to impose at least one further gradient on said field parallel to the planes of said slices.
References Cited (Backward Citations)
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