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5298864 Nuclear magnetic resonance spectrometer and method for measuring the nuclear magnetic resonance
New Patents
tion gradient, the phase encoding gradient, as well as, the read gradient are arranged orthogonally with respect to one another. Wherein, RF-pulses have a high frequency excitation profile, of which the base frequencies of the high frequency differ by a value Deltaf corresponding to the distance between the centers of adjacent layers or slices. Wherein different slices are excited by RF-pulses in cooperation with the selection gradient, and wherein, the amplitude and/or duration of the phase encoding gradient is varied. Slice selection frequencies for the recording of at least two phase encoding steps or groups of phase encoding steps and at most all phase encoding steps, which are allocated essentially to the same slice, differ by a frequency increment. Wherein, the allocation of the phase encoding steps to the excitation frequencies in each case is effected such that an almost continuous distribution of phase encoding steps across the measuring volume is achieved. Wherein, layers or slices which belong to a complete recording of the entire volume of the body area overlap one another in such a manner that within a random partial volume which: lies within the measuring volume, can be varied almost continuously, and has a thickness corresponding to deltaf + Deltaf, where Deltaf corresponds to the layer distance and deltaf represents the thickness of a selected layer or slice according to the bandwidth of the selective pulses.
5298863 MAGNETIC RESONANCE IMAGING APPARATUS HAVING A RESONANT CIRCUIT FOR GENERATING GRADIENT FIELDS, AND METHOD FOR OPERATING SAME Stefan Nowak, Franz Schmitt, Hubertu Fischer, Erlangen, Federal Republic Of Germany assigned to Siemens Aktiengesellschaft A gradient coil for generating a periodically changing read-out gradient in a magnetic resonance imaging apparatus is operated in a series resonant circuit having a capacitor. One of the elements of the series resonant circuit is charged before the beginning of each read-out gradient. The gradient coil can be charged with current, or the capacitor can be charged with voleither avoids or tage. Such operation significantly shortens the transient effect which occurs after excitation of the nuclear spins. The use of a series resonant circuit instead of a para-
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llel resonant circuit significantly reduces the voltage load on the gradient amplifier, so that the gradient amplifier can be constructed simpler and more inexpensively.
5298864 NUCLEAR MAGNETIC RESONANCE SPECTROMETER AND METHOD FOR MEASURING THE NUCLEAR MAGNETIC RESONANCE Detle Muller, Jean-Pierre Doutures, Francis Taulelle, Dominique Massiot, Malsch, Federal Republic Of Germany assigned to Bruker Analytische Messtechnik GmbH A nuclear magnetic resonance spectrometer comprises a sample holder being arranged in a constant magnetic field of a predetermined direction. The sample holder comprises a rotor adapted to receive a sample under investigation. The rotor is arranged to rotate the sample about a first axis being inclined to the predetermined direction at an acute angle of, preferably, 54.7 degrees. For heating up the rotor, a laser is provided emitting a laser beam which is directed upon a surface of the rotor. The laser beam is adjustable in intensity by means of a control device.
5299253 ALIGNMENT SYSTEM TO OVERLAY ABDOMINAL COMPUTER AIDED TOMOGRAPHY AND MAGNETIC RESONANCE ANATOMY WITH SINGLE PHOTON EMISSION TOMOGRAPHY Barry W Wessels assigned to Akzo N V The invention is a machine based alignment system for imaging with a contrasting marker (fiducial marker) attached to a support means for providing a set of markings which uniquely identify each cross-section of an imaged object in relation to other registered images. The invention also provides a method for using the alignment system.
tion gradient, the phase encoding gradient, as well as, the read gradient are arranged orthogonally with respect to one another. Wherein, RF-pulses have a high frequency excitation profile, of which the base frequencies of the high frequency differ by a value Deltaf corresponding to the distance between the centers of adjacent layers or slices. Wherein different slices are excited by RF-pulses in cooperation with the selection gradient, and wherein, the amplitude and/or duration of the phase encoding gradient is varied. Slice selection frequencies for the recording of at least two phase encoding steps or groups of phase encoding steps and at most all phase encoding steps, which are allocated essentially to the same slice, differ by a frequency increment. Wherein, the allocation of the phase encoding steps to the excitation frequencies in each case is effected such that an almost continuous distribution of phase encoding steps across the measuring volume is achieved. Wherein, layers or slices which belong to a complete recording of the entire volume of the body area overlap one another in such a manner that within a random partial volume which: lies within the measuring volume, can be varied almost continuously, and has a thickness corresponding to deltaf + Deltaf, where Deltaf corresponds to the layer distance and deltaf represents the thickness of a selected layer or slice according to the bandwidth of the selective pulses.
5298863 MAGNETIC RESONANCE IMAGING APPARATUS HAVING A RESONANT CIRCUIT FOR GENERATING GRADIENT FIELDS, AND METHOD FOR OPERATING SAME Stefan Nowak, Franz Schmitt, Hubertu Fischer, Erlangen, Federal Republic Of Germany assigned to Siemens Aktiengesellschaft A gradient coil for generating a periodically changing read-out gradient in a magnetic resonance imaging apparatus is operated in a series resonant circuit having a capacitor. One of the elements of the series resonant circuit is charged before the beginning of each read-out gradient. The gradient coil can be charged with current, or the capacitor can be charged with voleither avoids or tage. Such operation significantly shortens the transient effect which occurs after excitation of the nuclear spins. The use of a series resonant circuit instead of a para-
XIX
llel resonant circuit significantly reduces the voltage load on the gradient amplifier, so that the gradient amplifier can be constructed simpler and more inexpensively.
5298864 NUCLEAR MAGNETIC RESONANCE SPECTROMETER AND METHOD FOR MEASURING THE NUCLEAR MAGNETIC RESONANCE Detle Muller, Jean-Pierre Doutures, Francis Taulelle, Dominique Massiot, Malsch, Federal Republic Of Germany assigned to Bruker Analytische Messtechnik GmbH A nuclear magnetic resonance spectrometer comprises a sample holder being arranged in a constant magnetic field of a predetermined direction. The sample holder comprises a rotor adapted to receive a sample under investigation. The rotor is arranged to rotate the sample about a first axis being inclined to the predetermined direction at an acute angle of, preferably, 54.7 degrees. For heating up the rotor, a laser is provided emitting a laser beam which is directed upon a surface of the rotor. The laser beam is adjustable in intensity by means of a control device.
5299253 ALIGNMENT SYSTEM TO OVERLAY ABDOMINAL COMPUTER AIDED TOMOGRAPHY AND MAGNETIC RESONANCE ANATOMY WITH SINGLE PHOTON EMISSION TOMOGRAPHY Barry W Wessels assigned to Akzo N V The invention is a machine based alignment system for imaging with a contrasting marker (fiducial marker) attached to a support means for providing a set of markings which uniquely identify each cross-section of an imaged object in relation to other registered images. The invention also provides a method for using the alignment system.