Patent US2423697A successfully refreshed from Google Patents.
Patent EP0215592A2 successfully refreshed from Google Patents.
EP0215592A2
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Nuclear magnetic resonance imaging methods and apparatus
Assignee: Philips Design Ltd
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Filing: 1986-08-27
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Granted: —
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Expires: 2006-08-27
Abstract
Abstract A nuclear magnetic resonance imaging method and apparatus using the Hahn spin echo technique wherein dephasing of spins due to selection field gradients (G1x, G2x, G3x) applied during the radio frequency excitations pulses B1 (90°1. B2 (90°1, B3 (90°) of the Hahn technique is corrected solely by magnetic field gradients (-G'x, -G2'x) applied before the last radio frequency excitation pulse.
Inventors
- 👤 Ian Robert Young
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 19:33
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/4818; G01R33/482
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
176 words
A nuclear magnetic resonance imaging method wherein a representation of a selected region of a body is produced from data obtained by detection of spin echoes (E1, E2) produced by application of first, second and third radio frequency (RF) pulses (B1 (90°), B2 (90°) and B3 (90°))to the body in turn in the presence of a steady magnetic field defining an equilibrium direction on which is imposed during each RF pulse (B1 (90°), B2 (90°) and B3 (90°))a respective selection magnetic field gradient (G'x, G 2 x or G 3 x) to excite spins preferentially in the selected region, the time delay (tB) between the second and third RF pulses (B2 (90°) and B3 (90°))being such as to allow differentiation between parts of said selected region having different values of spin-lattice relaxation time constant, characterised in that dephasing of spins due to said selection gradients (G'x, G 2 x and G 3X ) is corrected solely by at least one further magnetic field gradient (-G'x, -G 2 'x) imposed before said third RF pulse (B3 (90°)).
Claim 2
Dependent Claim
176 words
A nuclear magnetic resonance imaging method wherein a representation of a selected region of a body is produced from data obtained by detection of spin echoes (E1, E2) produced by application of first, second and third radio frequency (RF) pulses (B1 (90°), B2 (90°) and B3 (90°))to the body in turn in the presence of a steady magnetic field defining an equilibrium direction on which is imposed during each RF pulse (B1 (90°), B2 (90°) and B3 (90°))a respective selection magnetic field gradient (G'x, G 2 x or G 3 x) to excite spins preferentially in the selected region, the time delay (tB) between the second and third RF pulses (B2 (90°) and B3 (90°))being such as to allow differentiation between parts of said selected region having different values of spin-lattice relaxation time constant, characterised in that dephasing of spins due to said selection gradients (G'x, G 2 x and G 3X ) is corrected solely by at least one further magnetic field gradient (-G'x, -G 2 'x) imposed before said third RF pulse (B3 (90°)).
Claim 3
Dependent Claim
48 words
A method according to Claim 1 wherein two said further magnetic field gradients (-G' 'x and -G 2 'x) are imposed each associated with a respective. one of the selection gradients (G'x and G 2 x) imposed during said first and second RF pulses (B1(90°), B2(90 0 )).
Claim 4
Dependent Claim
32 words
A method according to Claim 2 wherein said further gradients (-G' 'x, -G 2 'x) are imposed one (-G 2 'x) before and one (-G' 'x) after the respective associated selection gradient.
Claim 5
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)
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