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5347216 Fast NMR image acquisition with spectrally selective inversion pulse
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New Patents
vibration and deformation, the magnetic resonance imaging apparatus generates an accurate image signal without any acoustic noise.
5345178 METHOD FOR SETTING THE CURRENT THROUGH SHIM COILS AND GRADIENT COILS IN A NUCLEAR MAGNETIC RESONANCE APPARATUS Manabe Atsutaka; Kakimoto Shigefum; Wada Yasushiro Roettenbach, GERMANY Assigned to Siemens Aktiengesellschaft; Siemens-Asahi Medical Technologies L For calculating the magnetic field inhomogeneity, a gradient echo sequence or a spin echo sequence having a non-central 180 degrees radio-frequency pulse is first carried out. The nuclear magnetic resonance signal thus acquired is Fouriertransformed and the phase curve of the nuclear spins in a given region is identified. This is multiply repeated in different projections. The phase curves that are obtained are analyzed with a fit method and the coefficients of the spherical, harmonic functions describing the field distribution are identified therefrom. The current to be supplied to the individual shim coils and an offset current for the gradient coils can thus be calculated.
5346690 COMPOSITION OF A SUPERPARAMAGNETIC OR FERROMAGNETIC PARTICLE AND AN X-RAY CONTRAST AGENT FOR MRI Gundersen Helge G; Klaveness Jo Oslo, NORWAY Assigned to Nycomed Imaging AS PCT No. PCT/EP90/01195 Sec. 371 Date Jan. 21, 1992 Sec. 102(e) Date Jan. 21, 1992 PCT Filed Jul. 19, 1990 PCT Pub. No. WO91/01147 PCT Pub. Date Feb. 7, 1991. There is provided a magnetic resonance contrast medium comprising magnetically responsive particles and a physiologically tolerable osmoactive agent.
5347216 FAST NMR IMAGE ACQUISITION WITH SPECTRALLY SELECTIVE INVERSION PULSE Foo Thomas K Waukesha, WI, UNITED STATES Assigned to General Electric Company An NMR system performs a 3DFT scan using a set of steady-state free precession (SSFP) pulse sequences. A contrast preparation pulse sequence precedes each series of SSFP pulse sequences employed to acquire one plane through the threedimensional space, and it includes a spectrally selective RF inversion pulse tuned to fat or water. The sequence is repeated without any magnetization recovery delays until all the planes have been acquired.
5347217 MAGNETIC RESONANCE SPECTROSCOPY AND IMAGING Leach Martin 0; Sharp Jonathan C Wallington, UNITED KINGDOM Assigned to British Technology Group Limited PCT No. PCT/GB91/01%7 Sec. 371 Date Mar. 5, 1993 Sec. 102(e) Date Mar. 5, 1993 PCT Filed Jul. 25, 1991 PCT Pub. No. WO92/02828 PCT Pub. Date Feb. 20, 1992. In magnetic resonance spectroscopy or imaging, e.g. n.m.r. or e.s.r., a method of localizing the region of a sample from which a resonance signal is obtained by modulating the component Mz of magnetization in the Bo direction according to position in the sample. This is achieved by flipping the spins away from the Bo direction, applying a gradient magnetic field so that they lose or gain phase according to their position, refocussing the effects of any resonance offsets including chemical shifts and subsequently returning them to the Bo direction whereupon Mz depends on the phase lost or gained and thus the position. This may be repeated, possibly with different gradient fields or different phase pulses, to further localize the region before a resonance signal is finally detected. The contribution to the resonance signal varies with Mz and so is localiied to regions of greater Mz.
New Patents
vibration and deformation, the magnetic resonance imaging apparatus generates an accurate image signal without any acoustic noise.
5345178 METHOD FOR SETTING THE CURRENT THROUGH SHIM COILS AND GRADIENT COILS IN A NUCLEAR MAGNETIC RESONANCE APPARATUS Manabe Atsutaka; Kakimoto Shigefum; Wada Yasushiro Roettenbach, GERMANY Assigned to Siemens Aktiengesellschaft; Siemens-Asahi Medical Technologies L For calculating the magnetic field inhomogeneity, a gradient echo sequence or a spin echo sequence having a non-central 180 degrees radio-frequency pulse is first carried out. The nuclear magnetic resonance signal thus acquired is Fouriertransformed and the phase curve of the nuclear spins in a given region is identified. This is multiply repeated in different projections. The phase curves that are obtained are analyzed with a fit method and the coefficients of the spherical, harmonic functions describing the field distribution are identified therefrom. The current to be supplied to the individual shim coils and an offset current for the gradient coils can thus be calculated.
5346690 COMPOSITION OF A SUPERPARAMAGNETIC OR FERROMAGNETIC PARTICLE AND AN X-RAY CONTRAST AGENT FOR MRI Gundersen Helge G; Klaveness Jo Oslo, NORWAY Assigned to Nycomed Imaging AS PCT No. PCT/EP90/01195 Sec. 371 Date Jan. 21, 1992 Sec. 102(e) Date Jan. 21, 1992 PCT Filed Jul. 19, 1990 PCT Pub. No. WO91/01147 PCT Pub. Date Feb. 7, 1991. There is provided a magnetic resonance contrast medium comprising magnetically responsive particles and a physiologically tolerable osmoactive agent.
5347216 FAST NMR IMAGE ACQUISITION WITH SPECTRALLY SELECTIVE INVERSION PULSE Foo Thomas K Waukesha, WI, UNITED STATES Assigned to General Electric Company An NMR system performs a 3DFT scan using a set of steady-state free precession (SSFP) pulse sequences. A contrast preparation pulse sequence precedes each series of SSFP pulse sequences employed to acquire one plane through the threedimensional space, and it includes a spectrally selective RF inversion pulse tuned to fat or water. The sequence is repeated without any magnetization recovery delays until all the planes have been acquired.
5347217 MAGNETIC RESONANCE SPECTROSCOPY AND IMAGING Leach Martin 0; Sharp Jonathan C Wallington, UNITED KINGDOM Assigned to British Technology Group Limited PCT No. PCT/GB91/01%7 Sec. 371 Date Mar. 5, 1993 Sec. 102(e) Date Mar. 5, 1993 PCT Filed Jul. 25, 1991 PCT Pub. No. WO92/02828 PCT Pub. Date Feb. 20, 1992. In magnetic resonance spectroscopy or imaging, e.g. n.m.r. or e.s.r., a method of localizing the region of a sample from which a resonance signal is obtained by modulating the component Mz of magnetization in the Bo direction according to position in the sample. This is achieved by flipping the spins away from the Bo direction, applying a gradient magnetic field so that they lose or gain phase according to their position, refocussing the effects of any resonance offsets including chemical shifts and subsequently returning them to the Bo direction whereupon Mz depends on the phase lost or gained and thus the position. This may be repeated, possibly with different gradient fields or different phase pulses, to further localize the region before a resonance signal is finally detected. The contribution to the resonance signal varies with Mz and so is localiied to regions of greater Mz.