-
公开(公告)号：GB2102577A
公开(公告)日：1983-02-02
申请号：GB8211637
申请日：1982-04-22
Applicant: INDIANA UNIVERSITY FOUNDATION
Inventor： KAPLAN JEROME IRA
Abstract: In method for mapping the magnetization of nuclei in a planar region of a sample, the magnetisation of a selected (x - y) plane, normally in the z direction, is caused to rotate to the xy plane by known techniques. In one embodiment the plane is also subjected to a z-directed field with a gradient direction which rotates in the xy plane thereby producing a time dependent magnetic field whose time evolution (phase and amplitude) is unique to each point in the plane which causes the precession of magnetization at each point in the sensitive plane also to have a unique time dependence. Radio signals induced by the time variation of the magnetization are detected and subjected to a deconvolution integration technique to allow the magnetization for each point to be mathematically calculated. In second and third embodiments z-directed fields with (a) a fixed y-directed gradient and (b) an equal amplitude gradient directed so as to counter-rotate at the same frequency in the xy plane, are respectively present in addition to the first rotating gradient field.
-
公开(公告)号：DE3578951D1
公开(公告)日：1990-09-06
申请号：DE3578951
申请日：1985-05-29
Applicant: INDIANA UNIVERSITY FOUNDATION
Inventor： KAPLAN JEROME IRA
Abstract: improved two dimensional nuclear magnetic resonance imaging methods of the present invention are presented which comprises sensitizing a two dimensional slice of an object by standard procedures in a static magnetic field wherein the magnetization of the spins is transverse to the static field, applying a time varying magnetic field gradient to the sensitized two dimensional slice, detecting radiated electromagnetic energy from the two dimensional slice, and reconstructing spin information for each element within a slice from the detected radiated electromagnetic energy. In one aspect, the improvement is the use of an appropriate weighting function in the reconstruction to weight the detected radiation electromagnetic energy signals to compensate for the use of time varying magnetic field gradients that do not sample equal area elements of phase space in equal time intervals. In another independent aspect, almost any magnetic field gradient function may be used, that does not sample equal areas of phase space during equal time intervals, and a procedure defined by which spin information for equal areas of phase space is detected at unequal times. In yet another aspect, a uniquely specified class of time varying magnetic field gradient trajectories are defined which map equal area elements of two dimensional phase space in equal time intervals.
-
公开(公告)号：AT55188T
公开(公告)日：1990-08-15
申请号：AT85303745
申请日：1985-05-29
Applicant: INDIANA UNIVERSITY FOUNDATION
Inventor： KAPLAN JEROME IRA
Abstract: improved two dimensional nuclear magnetic resonance imaging methods of the present invention are presented which comprises sensitizing a two dimensional slice of an object by standard procedures in a static magnetic field wherein the magnetization of the spins is transverse to the static field, applying a time varying magnetic field gradient to the sensitized two dimensional slice, detecting radiated electromagnetic energy from the two dimensional slice, and reconstructing spin information for each element within a slice from the detected radiated electromagnetic energy. In one aspect, the improvement is the use of an appropriate weighting function in the reconstruction to weight the detected radiation electromagnetic energy signals to compensate for the use of time varying magnetic field gradients that do not sample equal area elements of phase space in equal time intervals. In another independent aspect, almost any magnetic field gradient function may be used, that does not sample equal areas of phase space during equal time intervals, and a procedure defined by which spin information for equal areas of phase space is detected at unequal times. In yet another aspect, a uniquely specified class of time varying magnetic field gradient trajectories are defined which map equal area elements of two dimensional phase space in equal time intervals.
-
-
Search Results
3
records
(took 0.021 seconds)
