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4996481 Magnetic resonance RF probe with electromagnetically isolated transmitter and receiver coils
VIII
New Patents
A substantially continuous image, recording motion of a portion of a sample, is provided by first NMR exciting, through use of a rotatinggradient ( rho) pulse signal, a relatively narrow cylindrical region, typically with diameter less than 1 inch, of magnetization intersecting the sample to be imaged and then acquiring the NMR response signal thus excited, in the presence of a readout gradient oriented along the length of the cylindrical excitation beam and establishing position thereon. A Fourier transformation of the acquired data allows display of a real-time record of the profile of the sample along the axis of the cylindrical probe beam. The cylinder-beam axis can be oriented in an arbitrary direction by proper mixing of the excitation and readout gradient fields; use of three orthogonal gradients in a Cartesian coordinate system is presently preferred. Spatial offsetting of the cyhndrical beam, from the center of the static magnetic field of the NMR imaging system, to any specific location within the system3 imaging volume, can be obtained by frequency modulation of the rho pulse RF waveform.
4996480 IMAGE RECONSTRUCTING DEVICE FOR USE IN MAGNETIC RESONANCE IMAGING APPARATUS Akira Maeda, Koichi Sano, Tetsuo Yokoyama, Hideaki Koizumi assigned to Hitachi Ltd A magnetic resonance signal is detected at a plurality of different periods of time in accordance with the phase shift of a plurality of chemical shift components while varying the intensity of a gradient magnetic field with time, a plurality of magnetic resonance signal thus obtained are used for estimating a magnetic resonance signal due to only a predetermined chemical shift component, the phase rotation of the predetermined chemical shift component is corrected in the estimated resonance signal, and further a blur due to chemical shift components other than the predetermined one is corrected to obtain a tomogram formed of only the predetermined chemical shift component. Alternatively, one measured resonance signal is modified by an image reconstruction algorithm peculiar to each of a plurality of chemical shift components, to obtain tomograms corresponding to the chemical shift components.
4996041 METHOD FOR INTRODUCING OXYGEN-17 INTO TISSUE FOR IMAGING IN A MAGNETIC RESONANCE IMAGING SYSTEM Toshiyuki Arai, Pradeep M Gupte, Sigmund E Lasker, Okazaki, Sakyo ku, Kyoto 606, NY, Japan A diagnostic imaging agent is provided for use in conjunction with a magnetic resonance imaging system for the imaging of spacial oxygen distribution in tissue. The imaging agent is comprised of a complex of oxygen-17, a biologically acceptable liquid carrier, such as a perfluorinated compound, and an emulsifying agent, and wherein the agent has an average particle size of less than about 0.6 microns, and an ionic composition essentially equal to that of blood. Useful information can be obtained, and in certain instances, therapy administered, by a non-envasive imaging technique relative to tissue perfusion by 19F-NMR (imaging of 19F) and oxygen utilization by lH-NMR (imaging of H2 170 as a metabolite).
4996481 MAGNETIC RESONANCE RF PROBE WITH ELECTROMAGNETICALLY ISOLATED TRANSMITTER AND RECEIVER CWLS Joseph J Ackerman, Wei Chen assigned to Washington University An RF probe for use in magnetic resonance applications includes a transmitter coil for transmitting RF energy to excite a specimen and a receiver coil for sensing the RF energy absorbed or emitted by the specimen wherein the receiver coil is electrically decoupled from the transmitter coil through the geometrical shape and positioning of the receiver coil with respect to the transmitter coil. Both the transmitter and receiver coils are used to produce wel1 defined RF magnetic fields. The technique includes the concept of physically locating multiple elements
New Patents
A substantially continuous image, recording motion of a portion of a sample, is provided by first NMR exciting, through use of a rotatinggradient ( rho) pulse signal, a relatively narrow cylindrical region, typically with diameter less than 1 inch, of magnetization intersecting the sample to be imaged and then acquiring the NMR response signal thus excited, in the presence of a readout gradient oriented along the length of the cylindrical excitation beam and establishing position thereon. A Fourier transformation of the acquired data allows display of a real-time record of the profile of the sample along the axis of the cylindrical probe beam. The cylinder-beam axis can be oriented in an arbitrary direction by proper mixing of the excitation and readout gradient fields; use of three orthogonal gradients in a Cartesian coordinate system is presently preferred. Spatial offsetting of the cyhndrical beam, from the center of the static magnetic field of the NMR imaging system, to any specific location within the system3 imaging volume, can be obtained by frequency modulation of the rho pulse RF waveform.
4996480 IMAGE RECONSTRUCTING DEVICE FOR USE IN MAGNETIC RESONANCE IMAGING APPARATUS Akira Maeda, Koichi Sano, Tetsuo Yokoyama, Hideaki Koizumi assigned to Hitachi Ltd A magnetic resonance signal is detected at a plurality of different periods of time in accordance with the phase shift of a plurality of chemical shift components while varying the intensity of a gradient magnetic field with time, a plurality of magnetic resonance signal thus obtained are used for estimating a magnetic resonance signal due to only a predetermined chemical shift component, the phase rotation of the predetermined chemical shift component is corrected in the estimated resonance signal, and further a blur due to chemical shift components other than the predetermined one is corrected to obtain a tomogram formed of only the predetermined chemical shift component. Alternatively, one measured resonance signal is modified by an image reconstruction algorithm peculiar to each of a plurality of chemical shift components, to obtain tomograms corresponding to the chemical shift components.
4996041 METHOD FOR INTRODUCING OXYGEN-17 INTO TISSUE FOR IMAGING IN A MAGNETIC RESONANCE IMAGING SYSTEM Toshiyuki Arai, Pradeep M Gupte, Sigmund E Lasker, Okazaki, Sakyo ku, Kyoto 606, NY, Japan A diagnostic imaging agent is provided for use in conjunction with a magnetic resonance imaging system for the imaging of spacial oxygen distribution in tissue. The imaging agent is comprised of a complex of oxygen-17, a biologically acceptable liquid carrier, such as a perfluorinated compound, and an emulsifying agent, and wherein the agent has an average particle size of less than about 0.6 microns, and an ionic composition essentially equal to that of blood. Useful information can be obtained, and in certain instances, therapy administered, by a non-envasive imaging technique relative to tissue perfusion by 19F-NMR (imaging of 19F) and oxygen utilization by lH-NMR (imaging of H2 170 as a metabolite).
4996481 MAGNETIC RESONANCE RF PROBE WITH ELECTROMAGNETICALLY ISOLATED TRANSMITTER AND RECEIVER CWLS Joseph J Ackerman, Wei Chen assigned to Washington University An RF probe for use in magnetic resonance applications includes a transmitter coil for transmitting RF energy to excite a specimen and a receiver coil for sensing the RF energy absorbed or emitted by the specimen wherein the receiver coil is electrically decoupled from the transmitter coil through the geometrical shape and positioning of the receiver coil with respect to the transmitter coil. Both the transmitter and receiver coils are used to produce wel1 defined RF magnetic fields. The technique includes the concept of physically locating multiple elements