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5614880 Superconducting magnet with symmetrical plural AIR gaps
XVI
PatentsALERT
Emulsions of paramagnetic contrast agents, and processes of making and using them are disclosed. The emulsions contain water, a dispersed oil phase and a complex of a paramagnetic metal ion and an organic acid chelator, for example DTPA (diethylenetriaminepentaacetic acid), having a ClO-C30 saturated aliphatic group and an hydroxyl group bonded to the nitrogen atom. The emulsions are very stable and therapeutically acceptable for intravenous administration to enhance MRI imaging.
5614826 METHODS FOR PREPULSING IN NUCLEAR MAGNETIC RESONANCE PULSE SEQUENCING Dixon W Thomas Atlanta, GA, UNITED assigned to Emory University
STATES
A composite spin lock prepulse method compensates for magnetic field inhomogeneities in objects or materials under study using nuclear magnetic resonance (NMR). The effective magnetic field seen by an object or material under study using NMR often is characterized by an which results in the off-resonance component, magnetization of the object or material having a component that diverges from the intended orientation after RF pulses. The method according to the present invention recognizes and utilizes the observation that aligning the off-resonance component of the magnetization in the x-z plane can be achieved when the amplitude of a preceding 90” y flip pulse is known, and that the effective field can be placed in alignment with the resulting magnetization, if necessary or desired, by adjusting the amplitude of the locking pulse as a function of the amplitude of the flip pulse. The method has been found to be particularly useful for enhancing contrast in images obtained using magnetic resonance imaging (MRI), and it may be conveniently applied in this and a wide variety of other NMR applications because pulse sequences of the present invention can be conveniently be inserted into existing NMR pulse sequences. In addition, the method may be used to create prepulse sequences having reduced net effective field amplitude and, thus, reduced SAR (heat absorption).
5614827 METHOD AND APPARATUS FOR SHIMMING A MAGNET SYSTEM OF A NUCLEAR MAGNETIC RESONANCE TOMOGRAPHY SYSTEM Heid Oliver Bern, SWITZERLAND Aktiengesellschaft
assigned to Siemens
In a method and apparatus for shimming a magnet system of a nuclear magnetic resonance tomography system, an apparatus-specific matrix is determined, which indicates the effect on the magnetic field for each shim channel. A phase difference matrix is subsequently formed by means of calculation of the phase differences between three-dimensional spatially resolved nuclear magnetic resonance raw data sets obtained with different echo times. This phase of difference matrix gives the field deviation for each pixel. In this phase difference matrix, the phase differences between consecutive pixels are calculated in several spatial directions, thereby determining a phase error data set. Finally, on the basis of the predefined matrix and of this phase error data set, currents for the individual shim channels are determined.
5614880 SUPERCONDUCTING MAGNET WITH SYMMETRICAL PLURAL AIR GAPS Palkovich Alex; Bird John M; Duby Toma UNITED KINGDOM assigned to Elscint Ltd
Oxford,
A super-conducting magnet for magnetic resonance imaging systems comprising symmetrically located back-to-back C-frame magnets.
5617859 APPARATUS AND METHODS FOR MAGNETIC RESONANCE (MR) IMAGING OF CAVITIES USING FLUIDS POLARIZED AT LOW TEMPERATURES Souza Steven P; Dumoulin Charles; Darrow Robert D; Cline Harvey E Williamstown, MA, UNITED STATES assigned to General Electric Company
PatentsALERT
Emulsions of paramagnetic contrast agents, and processes of making and using them are disclosed. The emulsions contain water, a dispersed oil phase and a complex of a paramagnetic metal ion and an organic acid chelator, for example DTPA (diethylenetriaminepentaacetic acid), having a ClO-C30 saturated aliphatic group and an hydroxyl group bonded to the nitrogen atom. The emulsions are very stable and therapeutically acceptable for intravenous administration to enhance MRI imaging.
5614826 METHODS FOR PREPULSING IN NUCLEAR MAGNETIC RESONANCE PULSE SEQUENCING Dixon W Thomas Atlanta, GA, UNITED assigned to Emory University
STATES
A composite spin lock prepulse method compensates for magnetic field inhomogeneities in objects or materials under study using nuclear magnetic resonance (NMR). The effective magnetic field seen by an object or material under study using NMR often is characterized by an which results in the off-resonance component, magnetization of the object or material having a component that diverges from the intended orientation after RF pulses. The method according to the present invention recognizes and utilizes the observation that aligning the off-resonance component of the magnetization in the x-z plane can be achieved when the amplitude of a preceding 90” y flip pulse is known, and that the effective field can be placed in alignment with the resulting magnetization, if necessary or desired, by adjusting the amplitude of the locking pulse as a function of the amplitude of the flip pulse. The method has been found to be particularly useful for enhancing contrast in images obtained using magnetic resonance imaging (MRI), and it may be conveniently applied in this and a wide variety of other NMR applications because pulse sequences of the present invention can be conveniently be inserted into existing NMR pulse sequences. In addition, the method may be used to create prepulse sequences having reduced net effective field amplitude and, thus, reduced SAR (heat absorption).
5614827 METHOD AND APPARATUS FOR SHIMMING A MAGNET SYSTEM OF A NUCLEAR MAGNETIC RESONANCE TOMOGRAPHY SYSTEM Heid Oliver Bern, SWITZERLAND Aktiengesellschaft
assigned to Siemens
In a method and apparatus for shimming a magnet system of a nuclear magnetic resonance tomography system, an apparatus-specific matrix is determined, which indicates the effect on the magnetic field for each shim channel. A phase difference matrix is subsequently formed by means of calculation of the phase differences between three-dimensional spatially resolved nuclear magnetic resonance raw data sets obtained with different echo times. This phase of difference matrix gives the field deviation for each pixel. In this phase difference matrix, the phase differences between consecutive pixels are calculated in several spatial directions, thereby determining a phase error data set. Finally, on the basis of the predefined matrix and of this phase error data set, currents for the individual shim channels are determined.
5614880 SUPERCONDUCTING MAGNET WITH SYMMETRICAL PLURAL AIR GAPS Palkovich Alex; Bird John M; Duby Toma UNITED KINGDOM assigned to Elscint Ltd
Oxford,
A super-conducting magnet for magnetic resonance imaging systems comprising symmetrically located back-to-back C-frame magnets.
5617859 APPARATUS AND METHODS FOR MAGNETIC RESONANCE (MR) IMAGING OF CAVITIES USING FLUIDS POLARIZED AT LOW TEMPERATURES Souza Steven P; Dumoulin Charles; Darrow Robert D; Cline Harvey E Williamstown, MA, UNITED STATES assigned to General Electric Company