EP0223543A2
Expired / Lapsed
EP
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Nuclear magnetic resonance imaging
Assignee: Philips Design Ltd
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Filing: 1986-11-12
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Granted: —
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Expires: 2006-11-12
Abstract
Abstract In a steady state free precession (SFP) magnetic resonance imaging method, after each pulse (1) of an applied train of phase coherent RF pulses which excite magnetic resonance spins in a region of a body being examined, magnetic field gradients (7, 11) are applied to encode the excited spins and the encoded spins are detected, and at least one further magnetic field gradient (15, 17) is then applied to rephase the spins by the time the next RF pulse is applied. The method finds particular application where the applied encoding gradients serve to encode the spins in such a manner as to allow a multi-dimensional Fourier transform technique to be used to reconstruct an image. The method allows more rapid data acquisition than has been possible hitherto in SFP imaging.
Inventors
- 👤 Michael Laurence Gyngell
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 11:06
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/4818; G01R33/482; G01R33/4822; G01R33/54; G01R33/56; G01R33/561; G01R33/5613
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
146 words
A nuclear magnetic resonance imaging method including the step of applying a train of phase coherent radio frequency pulses (1 or 19) to a body in the presence of a steady magnetic field which defines an equilibrium axis of magnetic alignment in the body to excite steady state nuclear magnetic spins in a region of the body to be examined characterised in that: after each said radio frequency pulse (1 or 19) at least one encoding magnetic field gradient (7, 11 or 27, 21, 23) is applied to encode the excited spins, the encoded spins are detected; and after each such detection at least one rephasing magnetic field gradient (15, 17 or 31, 33, 35) is applied effective to rephase spins by the time the next radio frequency pulse (1 or 19) is applied; the detected spins being utilised to reconstruct an image of said region.
Claim 2
Dependent Claim
146 words
A nuclear magnetic resonance imaging method including the step of applying a train of phase coherent radio frequency pulses (1 or 19) to a body in the presence of a steady magnetic field which defines an equilibrium axis of magnetic alignment in the body to excite steady state nuclear magnetic spins in a region of the body to be examined characterised in that: after each said radio frequency pulse (1 or 19) at least one encoding magnetic field gradient (7, 11 or 27, 21, 23) is applied to encode the excited spins, the encoded spins are detected; and after each such detection at least one rephasing magnetic field gradient (15, 17 or 31, 33, 35) is applied effective to rephase spins by the time the next radio frequency pulse (1 or 19) is applied; the detected spins being utilised to reconstruct an image of said region.
Claim 3
Dependent Claim
51 words
A method according to Claim 1 wherein said at least one encoding magnetic field gradient comprises a phase encoding gradient (7, 21 or 23) and said at least one rephasing gradient comprises a gradient (17, 33 or 35) corresponding to said encoding gradient (7, 21 or 23) but of reverse direction.
Claim 4
Dependent Claim
25 words
A method according to Claim 1 wherein said at least one encoding magnetic field gradient comprises a read gradient (11 or 27) applied during detection.
Claim 5
Dependent Claim
64 words
A method according to Claim 3 wherein said read gradient is preceded by a gradient (9 or 25) of reverse direction to compensate for dephasing of spins during application of said read gradient (11 or 27) and said at least one rephasing gradient (15 or 21) is in the same direction as said gradient (9 or 25) preceding said read gradient (11 or 27).
Claim 6
Dependent Claim
33 words
A method according to Claim 1 wherein said encoding magnetic field gradients (7 or 21, 23) are such as to allow a multi-dimensional Fourier transform technique to be used to reconstruct said image.
Claim 7
Dependent Claim
55 words
A method according to Claim 1 wherein each said radio frequency pulse (1 or 19) is applied in the presence of a selection magnetic field gradient (3) and said at least one rephasing magnetic field gradient compensates for dephasing of spins due to the selection magnetic field gradient associated with the next radio frequency pulse.
Claim 8
Dependent Claim
20 words
A nuclear magnetic resonance imaging apparatus arranged to carry out a method according to any one of the preceding claims.
References Cited (Backward Citations)
No citation records indexed.
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