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4740751 Whole body MRI resonator
New Patents
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4740748
4740750
METHOD OF HIGH-SPEED MAGNETIC RESONANCE IMAGING
RECEPTION SIGNAL PROCESSING APPARATUS IN NUCLEAR MAGNETIC RESONANCE DIAGNOSTIC APPARATUS
Richard R Rzedzian NMR Systems Inc
assigned
to Advanced
A method of high-speed magnetic resonance imaging in which the object to be imaged is placed in a high static magnetic field. Nuclear spins are excited in an image area in a selected plane of the object by superimposing a slice-selection gradient along an axis and applying a pulse of radio frequency magnetic field. Following an encoding pulse sequence and rephasing of the nuclear spins by the application of a 180 degrees radio frequency pulse, mutually orthogonal phaseencoding and readout gradients are alternately applied in the image plane to effect a traversal through spatial frequency domain (k-space). If phase errors vary slowly in time, only a partial kspace trajectory is required. Chemical shift is eliminated either by the application of a suppression pulse of RF field or by tailoring the frequency spectrum of the rephasing pulse so as to preclude rephasing of one or other of the chemical moieties.
Yoshio Machida, Nishinasuno, Japan assigned to Tokyo Shibaura Denki Kabushiki Kaisha Reception signal processing apparatus in nuclear magnetic resonance diagnostic apparatus to display as an image the distribution of the spin density or relaxation time of specific atomic nuclei existing in an object utilizing nuclear magnetic resonance phenomena including a phase demodulator for phase demodulating a nuclear magnetic resonance signal evoked by nuclear magnetic resonance phenomena in accordance with two reference waves, the phases of which are different by 90 convertor for degrees, an analog-to-digital digitalizing the separated two signals obtained by the phase demodulator, and a noise correction processor for eliminating the low frequency component noises included in the demodulated signals from the phase demodulator to obtain an image without artifacts.
4740749 4740751 NMR IMAGING METHOD WHOLE BODY MRI RESONATOR Etsuj Yamamoto, Hideki Kohno, Japan assigned to Hitachi Ltd
Akishima,
In an imaging method called spin warp method in which a measuring sequence inclusive of nuclear spin excitation, application of phaseencoding gradient field, and measurement of NMR signals under the application of read-out gradient field, is repeated while changing the phase-encoding amount, and a data train thus obtained is subjected to the two-dimensional inverse Fourier transformation to reconstruct a magnetization distribution image of an object, wherein an NMR imaging method is characterized in that measurement of NMR signals is repeated a plural number of times for a particular phase-encoding amount only among many phase-encoding amounts, a plurality of NMR signals thus obtained are added up together and are averaged, and the data obtained by the addition and averaging is subjected to the two-dimensional inverse Fourier transformation.
George Misic, John Patrick assigned to Picker International Inc A resonator coil assembly (32) includes a dielectric sleeve (40) on which a first resonator coil portion (42) and a second resonator coil portion (44), each of copper foil, are adhered. The dielectric sleeve is dimensioned to receive a human torso therein and in one embodiment (FIG. 1) is circular in cross section and in another (FIG. 4) is elliptical in cross section. A pair of adjustable tuning capacitances (64, 66) and a pair of adjustable matching capacitances (68,70) are interconnected between one end of the each coil portion and a metal bore liner (54). An opposite end of the coil portions are capacitively coupled to each other (FIG. 1) or to the bore liner (FIG. 3). A half wave length cable (72) interconnects the junctions between the first and second tuning and matching capacitances. One of these junctions is connected by a cable (74) with a radio frequency generator (30) and a radio receiver (34).
V
4740748
4740750
METHOD OF HIGH-SPEED MAGNETIC RESONANCE IMAGING
RECEPTION SIGNAL PROCESSING APPARATUS IN NUCLEAR MAGNETIC RESONANCE DIAGNOSTIC APPARATUS
Richard R Rzedzian NMR Systems Inc
assigned
to Advanced
A method of high-speed magnetic resonance imaging in which the object to be imaged is placed in a high static magnetic field. Nuclear spins are excited in an image area in a selected plane of the object by superimposing a slice-selection gradient along an axis and applying a pulse of radio frequency magnetic field. Following an encoding pulse sequence and rephasing of the nuclear spins by the application of a 180 degrees radio frequency pulse, mutually orthogonal phaseencoding and readout gradients are alternately applied in the image plane to effect a traversal through spatial frequency domain (k-space). If phase errors vary slowly in time, only a partial kspace trajectory is required. Chemical shift is eliminated either by the application of a suppression pulse of RF field or by tailoring the frequency spectrum of the rephasing pulse so as to preclude rephasing of one or other of the chemical moieties.
Yoshio Machida, Nishinasuno, Japan assigned to Tokyo Shibaura Denki Kabushiki Kaisha Reception signal processing apparatus in nuclear magnetic resonance diagnostic apparatus to display as an image the distribution of the spin density or relaxation time of specific atomic nuclei existing in an object utilizing nuclear magnetic resonance phenomena including a phase demodulator for phase demodulating a nuclear magnetic resonance signal evoked by nuclear magnetic resonance phenomena in accordance with two reference waves, the phases of which are different by 90 convertor for degrees, an analog-to-digital digitalizing the separated two signals obtained by the phase demodulator, and a noise correction processor for eliminating the low frequency component noises included in the demodulated signals from the phase demodulator to obtain an image without artifacts.
4740749 4740751 NMR IMAGING METHOD WHOLE BODY MRI RESONATOR Etsuj Yamamoto, Hideki Kohno, Japan assigned to Hitachi Ltd
Akishima,
In an imaging method called spin warp method in which a measuring sequence inclusive of nuclear spin excitation, application of phaseencoding gradient field, and measurement of NMR signals under the application of read-out gradient field, is repeated while changing the phase-encoding amount, and a data train thus obtained is subjected to the two-dimensional inverse Fourier transformation to reconstruct a magnetization distribution image of an object, wherein an NMR imaging method is characterized in that measurement of NMR signals is repeated a plural number of times for a particular phase-encoding amount only among many phase-encoding amounts, a plurality of NMR signals thus obtained are added up together and are averaged, and the data obtained by the addition and averaging is subjected to the two-dimensional inverse Fourier transformation.
George Misic, John Patrick assigned to Picker International Inc A resonator coil assembly (32) includes a dielectric sleeve (40) on which a first resonator coil portion (42) and a second resonator coil portion (44), each of copper foil, are adhered. The dielectric sleeve is dimensioned to receive a human torso therein and in one embodiment (FIG. 1) is circular in cross section and in another (FIG. 4) is elliptical in cross section. A pair of adjustable tuning capacitances (64, 66) and a pair of adjustable matching capacitances (68,70) are interconnected between one end of the each coil portion and a metal bore liner (54). An opposite end of the coil portions are capacitively coupled to each other (FIG. 1) or to the bore liner (FIG. 3). A half wave length cable (72) interconnects the junctions between the first and second tuning and matching capacitances. One of these junctions is connected by a cable (74) with a radio frequency generator (30) and a radio receiver (34).