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4707660 Fast method and device for determining an NMR distribution in a region of a body
Mognefic Resonance Imagmg, Vol. 6, pp. I-XIII, Printed in the USA. All rights reserved.
1988 Copyright
0730-725X/88 $3.00 + .OO 0 1988 Pcrgamon Press plc
NEW PATENTS This Section contains abstracts and, where appropriate, illustrations of recently issued United States patents and published patent applications filed from over 30 countries under the Patent Cooperation Treaty. This information was obtained from recent additions to the Pergamon PATSEARCH’@ online database in accordance with interest profiles developed by the Editors. Further information about Pergamon PATSEARCH” can be obtained from
Pergamon Orbit InfoLine Inc., 8000 Westpark Drive, McLean, Virginia 22102 U.S.A. Copies of complete patents announced in this Section are available from Pergamon Orbit InfoLine Inc. for $8 per copy. Payment with order is required. Orders outside North America add $2 for air postage. Order by patent number for Pergamon Orbit InfoLine only.
4707658 METHOD OF RAPID ACQUISITION OF SPIN RESONANCE DATA FOR A SPATIALLY RESOLVED INVESTIGATION OF AN OBJECT Jens Frahm, Axe1 Haase, Dieter Matthaei, Wolfgang Haenicke, Klaus-Dietmar Merboldt, Goettingen, Federal Republic Of Germany assigned to Max-Planck-Gesellschaft zur Foerderung der Wissenschaften e V A fast low angle shot ( FLASH ) NMR method is described, which uses radio frequency excitation pulses having a flip angle substantially less than 90 degrees, and subsequent reading gradient reversal for producing a gradient echo signal. The small flip angle pulses create an equilibrium state between longitudinal and transverse magnetization, which allows to apply the radio frequency pulses repeatedly with high repetition rate to produce gradient echo signals of essentially equal strength, without any intervening delay for magnetization restoration or recovery.
4707659 METHOD AND DEVICE FOR DETERMINING AN NMR DISTRIBUTION IN A REGION OF A BODY Dietmar W Kunz, Hans H Tuithof, Johannes J M Cuppen, Hamburg, Federal Republic Of Germany assigned to U S Philips Corporation The method and device for NMR Fourier zeugmatography utilizes amplitude-modulated r.f.
pulses (90 degrees and 180 degrees pulses) for the excitation of nuclear spins and the generating of nuclear spin echo signals. For three-dimensional Fourier zeugmatography, r.f. pulse having a large bandwidth (for example lo-50 kHz) are desired. The use of amplitude-modulated signals then implies an undesirably high peak power of the r.f. generator. In accordance with the invention, use is made of a frequency-modulated signal which can have a substantially constant amplitude and which preferably covers the desired frequency spectrum at a uniform speed.
4707660 FAST METHOD AND DEVICE FOR DETERMINING AN NMR DISTRIBUTION IN A REGION OF A BODY Johannes J M Cuppen, Johannes P Groen, Eindhoven, Netherlands assigned to U S Philips Corporation The invention relates to the determination of an NMR distribution in which an alternating gradient field is applied while sampling the NMR signal (FID signal, nuclear spin echo signal). The frequency of the alternating gradient field is comparatively low (order of magnitude of 100 Hz) and the field has from a few to some tens of cycles during each measurement period. While an FID signal is being sampled, the image frequency field matrix is scanned using a zig-zag (oscillating) line pattern during each line when data is provided for elements in from a few to some tens of rows in the image frequency matrix. By applying preparation gradient fields, the image frequency matrix can be filled by means of successive zig-zag line patterns which have been shifted with respect to one another and which thus enable a uniform sampling density to be
II
New Patents
provided in the image frequency space. The filling of the image frequency matrix with signal samples is thus speeded up by a factor of a few to some tens of times by the invention, the energy required for controlling the gradient field coils being substantially reduced at the same time.
4707661 MACHINE GENERATION OF MACHINE-EXECUTABLE STATECHANGE INSTRUCTIONS FOR MAGNETIC RESONANCE IMAGING John C Hoenninger, Lawrence Crooks assigned to The Regents of the University of California An assembler/linker process utilizes predetermined control program segments ( templates defining a sub-sequence of magnetic resonance imaging (MRI) states) together with predetermined program-change tables of MRI parameter values. At least some of the program segments are referenced by predetermined addresses and include pointersymbolic references to corresponding ones of the table entries. The assembler/linker process machine set of such replicates a predetermined slice/specific program segments in a predetermined order while also simultaneously indexing corresponding symbolic addresses and referenced table entries in a predetermined sequence so as to maintain proper correspondence between slice-specific main programs and subroutines for each replicated program segment. In addition, certain of the replicated program segments may be defined having predetermined symbolic addresses which are not indexed thus further conserving the number of program instructions which need to be replicated and stored in the assembly/linkage process. A subset of slice-specific program segments can be further designated for replication as a unit before following program segments are utilized. A unique linker language level syntax is also provided for an ordered string of input digital data used to control the assembler/linker replication process.
4707663 NUCLEAR MAGNETIC RESONANCE APPARATUS USING LOW ENERGY MAGNETIC ELEMENTS Lawrence A Minkoff, Gordon Danby assigned to Fonar Corporation
An NMR scanner apparatus uses a permanent magnet comprised of an assembly of magnetic material formed of a substantial number of low energy permanent magnetic elements producing magnetic flux and arranged in at least one row of columns. A frame of magnetically soft material provides a return path for the magnetic flux and provides a surface from which the columns of magnetic elements extend. A flux concentrator plate is disposed adjacent to a surface of the assembly and recessed a sufficient distance from the edge of the assembly to inhibit the loss of magnetic flux. The flux concentrator plate and the frame sandwich the magnetic assembly therebetween. A pole piece consisting of a soft magnetic material is disposed adjacent to a surface of the flux concentrator plate. The pole piece defines a scanning area substantially smaller than the area of the adjacent surface of the flux concentrator plate such that the pole piece exhibits parallel lines of magnetic flux for inducing polarization in living tissue.
4707797 FUNCTION GENERATOR NMR SYSTEM
FOR
Randal Briggs assigned to Advanced NMR Systems Inc A modular function generator for generating a plurality of analog waveforms for use in an NMR imaging system. The function generator includes a plurality of waveform synthesizer modules which are interconnected by a main bus to a central controller CPU. Each synthesizer is adapted to produce one analog waveform for the NMR imaging system. A synthesizer module includes a memory and an address sequencer which produces a sequence of addresses which control the retrieval of data from the memory. Each data world of the memory contains several fields. An instruction field and a general data field control the address sequencer so that the sequence of addresses is, in turn, controlled by the memory data. Other fields from the memory define analog and digital outputs produced by the synthesizer module. The fields are generated by program control means which are organized to have data segments which define a set of elementary analog waveform segments and subroutines which are controlled by a main program. The execution of each subroutine produces a segment of an analog waveform. The subroutines generate a segment by accessing given data segments and concatenating a plurality of elementary segments into a single
1988 Copyright
0730-725X/88 $3.00 + .OO 0 1988 Pcrgamon Press plc
NEW PATENTS This Section contains abstracts and, where appropriate, illustrations of recently issued United States patents and published patent applications filed from over 30 countries under the Patent Cooperation Treaty. This information was obtained from recent additions to the Pergamon PATSEARCH’@ online database in accordance with interest profiles developed by the Editors. Further information about Pergamon PATSEARCH” can be obtained from
Pergamon Orbit InfoLine Inc., 8000 Westpark Drive, McLean, Virginia 22102 U.S.A. Copies of complete patents announced in this Section are available from Pergamon Orbit InfoLine Inc. for $8 per copy. Payment with order is required. Orders outside North America add $2 for air postage. Order by patent number for Pergamon Orbit InfoLine only.
4707658 METHOD OF RAPID ACQUISITION OF SPIN RESONANCE DATA FOR A SPATIALLY RESOLVED INVESTIGATION OF AN OBJECT Jens Frahm, Axe1 Haase, Dieter Matthaei, Wolfgang Haenicke, Klaus-Dietmar Merboldt, Goettingen, Federal Republic Of Germany assigned to Max-Planck-Gesellschaft zur Foerderung der Wissenschaften e V A fast low angle shot ( FLASH ) NMR method is described, which uses radio frequency excitation pulses having a flip angle substantially less than 90 degrees, and subsequent reading gradient reversal for producing a gradient echo signal. The small flip angle pulses create an equilibrium state between longitudinal and transverse magnetization, which allows to apply the radio frequency pulses repeatedly with high repetition rate to produce gradient echo signals of essentially equal strength, without any intervening delay for magnetization restoration or recovery.
4707659 METHOD AND DEVICE FOR DETERMINING AN NMR DISTRIBUTION IN A REGION OF A BODY Dietmar W Kunz, Hans H Tuithof, Johannes J M Cuppen, Hamburg, Federal Republic Of Germany assigned to U S Philips Corporation The method and device for NMR Fourier zeugmatography utilizes amplitude-modulated r.f.
pulses (90 degrees and 180 degrees pulses) for the excitation of nuclear spins and the generating of nuclear spin echo signals. For three-dimensional Fourier zeugmatography, r.f. pulse having a large bandwidth (for example lo-50 kHz) are desired. The use of amplitude-modulated signals then implies an undesirably high peak power of the r.f. generator. In accordance with the invention, use is made of a frequency-modulated signal which can have a substantially constant amplitude and which preferably covers the desired frequency spectrum at a uniform speed.
4707660 FAST METHOD AND DEVICE FOR DETERMINING AN NMR DISTRIBUTION IN A REGION OF A BODY Johannes J M Cuppen, Johannes P Groen, Eindhoven, Netherlands assigned to U S Philips Corporation The invention relates to the determination of an NMR distribution in which an alternating gradient field is applied while sampling the NMR signal (FID signal, nuclear spin echo signal). The frequency of the alternating gradient field is comparatively low (order of magnitude of 100 Hz) and the field has from a few to some tens of cycles during each measurement period. While an FID signal is being sampled, the image frequency field matrix is scanned using a zig-zag (oscillating) line pattern during each line when data is provided for elements in from a few to some tens of rows in the image frequency matrix. By applying preparation gradient fields, the image frequency matrix can be filled by means of successive zig-zag line patterns which have been shifted with respect to one another and which thus enable a uniform sampling density to be
II
New Patents
provided in the image frequency space. The filling of the image frequency matrix with signal samples is thus speeded up by a factor of a few to some tens of times by the invention, the energy required for controlling the gradient field coils being substantially reduced at the same time.
4707661 MACHINE GENERATION OF MACHINE-EXECUTABLE STATECHANGE INSTRUCTIONS FOR MAGNETIC RESONANCE IMAGING John C Hoenninger, Lawrence Crooks assigned to The Regents of the University of California An assembler/linker process utilizes predetermined control program segments ( templates defining a sub-sequence of magnetic resonance imaging (MRI) states) together with predetermined program-change tables of MRI parameter values. At least some of the program segments are referenced by predetermined addresses and include pointersymbolic references to corresponding ones of the table entries. The assembler/linker process machine set of such replicates a predetermined slice/specific program segments in a predetermined order while also simultaneously indexing corresponding symbolic addresses and referenced table entries in a predetermined sequence so as to maintain proper correspondence between slice-specific main programs and subroutines for each replicated program segment. In addition, certain of the replicated program segments may be defined having predetermined symbolic addresses which are not indexed thus further conserving the number of program instructions which need to be replicated and stored in the assembly/linkage process. A subset of slice-specific program segments can be further designated for replication as a unit before following program segments are utilized. A unique linker language level syntax is also provided for an ordered string of input digital data used to control the assembler/linker replication process.
4707663 NUCLEAR MAGNETIC RESONANCE APPARATUS USING LOW ENERGY MAGNETIC ELEMENTS Lawrence A Minkoff, Gordon Danby assigned to Fonar Corporation
An NMR scanner apparatus uses a permanent magnet comprised of an assembly of magnetic material formed of a substantial number of low energy permanent magnetic elements producing magnetic flux and arranged in at least one row of columns. A frame of magnetically soft material provides a return path for the magnetic flux and provides a surface from which the columns of magnetic elements extend. A flux concentrator plate is disposed adjacent to a surface of the assembly and recessed a sufficient distance from the edge of the assembly to inhibit the loss of magnetic flux. The flux concentrator plate and the frame sandwich the magnetic assembly therebetween. A pole piece consisting of a soft magnetic material is disposed adjacent to a surface of the flux concentrator plate. The pole piece defines a scanning area substantially smaller than the area of the adjacent surface of the flux concentrator plate such that the pole piece exhibits parallel lines of magnetic flux for inducing polarization in living tissue.
4707797 FUNCTION GENERATOR NMR SYSTEM
FOR
Randal Briggs assigned to Advanced NMR Systems Inc A modular function generator for generating a plurality of analog waveforms for use in an NMR imaging system. The function generator includes a plurality of waveform synthesizer modules which are interconnected by a main bus to a central controller CPU. Each synthesizer is adapted to produce one analog waveform for the NMR imaging system. A synthesizer module includes a memory and an address sequencer which produces a sequence of addresses which control the retrieval of data from the memory. Each data world of the memory contains several fields. An instruction field and a general data field control the address sequencer so that the sequence of addresses is, in turn, controlled by the memory data. Other fields from the memory define analog and digital outputs produced by the synthesizer module. The fields are generated by program control means which are organized to have data segments which define a set of elementary analog waveform segments and subroutines which are controlled by a main program. The execution of each subroutine produces a segment of an analog waveform. The subroutines generate a segment by accessing given data segments and concatenating a plurality of elementary segments into a single