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5594337 Local coil for magnetic resonance angiography
Patents
echo data output from the receiver on the Fourier space. Finally, the imaging apparatus has an input unit for adjusting a reference strength of the phase-encoding gradient magnetic field pulse so that echo data corresponding to spatial frequencies in the phase-encoding direction, which are the inverse and an integral multiple of a predetermined period of the periodic structure of the non-magnetic material in the phantom, is maximized.
ALERT
XXVII
apparatus wherein the amount of comparison operation processing of a bit allocator is minimized. A subband filter divides a PCM signal into and outputs a plurality of frequency subbands. A SMR calculator calculates, for each of the frequency subbands, an SMR which is a ratio between a signal level and a mask level. A bit allocator calculates a reference NMR which is a value obtained by subtracting, from an SMR of the entire frequency band, a S/N ratio calculated from a reference bit number to be allocated to one of the frequency subbands which exhibits a maximum SMR, and adjusts the reference NMR to perform bit allocation to the frequency subbands.
5587658 5594336
SHIMMING METHOD FOR NMR MAGNET USING UNSHIELDED GRADIENT SYSTEMS Sukumar STATES
Subramaniam Union City, CA, assigned to Bruker Instruments Inc
UNITED
An method for determining the inhomogeneities of the magnetic field of the magnet of an NMR system makes use of unshielded coils while minimizing the effect of eddy currents induced in the magnet components by the gradient fields. A first dataset is acquired by ramping the level of a gradient magnetic field to a maximum value and generating an RF pulse to excite the spins. After a delay time tl, a single data point is sampled. While the spins are allowed to relax, the gradient field magnitude is changed to the next level. Another RF pulse is generated and, after time t 1, the next data point is sampled. This process continues until a first complete dataset is acquired. The next gradient function is then applied in a similar manner, and the data points sampled after an RF pulse and a delay time of t2. During sampling of the second dataset, the gradient area for each spatial data point is equal to the gradient area for that spatial point during sampling of the first dataset. After the second dataset is acquired, a frequency distribution for the gradient direction is obtained using known techniques.
5588024
FREQUENCY
Takano Hidet Corporation The invention
SUBBAND APPARATUS Tokyo,
provides
JAPAN
a frequency
THREE POINT TECHNIQUE USING SPIN AND GRADIENT ECHOES FOR WATER/FAT SEPARATION
ENCODING
assigned
to NEC
subband
encoding
Gullapalli Rao P; Liu Haiying; Loncar Mark J Richmond Heights, OH, UNITED STATES assigned to Picker International Inc Magnetic resonance is excited in first and second species dipoles of a subject in a temporally constant magnetic field. The resonance is refocused to generate a spin echo centered at a time when the first and second species resonance signals are in-phase. Gradients echoes are generated, centered at a time (2n+l) pi/ delta omega before and after the spin echo, where delta omega is a difference between the first and second species resonance frequencies. In this manner, the first and second species signals are 180 degrees out-of-phase in the gradient echoes. The resonance is refocused one or more times to generate additional spin and gradient echoes with different phase encodings. The sequence is repeated with yet more phase encodings, and magnetic resonance signals from the spin echo and the two gradient echoes are reconstructed into a spin echo image (SO) and a pair of gradient echo images (s+ 1, s-l). A phase map is generated from the spin and gradient echo images. One of the gradient echo images is corrected with the phase map. The phase corrected gradient image is additively combined with the spin echo image to generate a first species image and is subtractively combined to generate a second species image.
5594337
LOCAL COIL FOR MAGNETIC RESONANCE ANGIOGRAPHY
XXVIII
Patents
Menomonee Falls, WI, UNITED Boskamp Eddy STATES assignedto Medical Advances Inc An angiographiccoil for performing blood flow studiesof
the large vesselsof the legs and lower pelvis employs an alternating series of coil elements having orthogonal sensitivities arrayed along a cover and basesurrounding the legs and lower pelvis and supported thereby. The alternatingcoil patternprovides good isolationbetweenthe coils in a coil that allows easy patient positioning. In a second embodiment, structures having conductors pass betweenthe legswhen the patient’slegsstraddle a divider of the coil form. The coil structure is open on sidesto permit easyentrance and exit from the coil by the patient. Multiple coils are usedto spanthe length of the elongate imaging area of the legs and a pre-amplifier network is employedto limit the inductancebetweenother coil and to provide for piecewiseimaging of the entire leg and pelvis region.
5594338 AUTOMATIC TUNING APPARATUS AND METHOD FOR SUBSTANCE DETECTION USING NUCLEAR QUADRUPOLE RESONANCE AND NUCLEAR MAGNETIC RESONANCE Magnuson Erik E Escondido, CA, UNITED STATES assignedto Quantum Magnetics Inc Apparatus for tuning a system for detecting a target substancethrough the useof nuclearquadrupoleresonance (NQR) or nuclear magnetic resonance (NMR). The apparatustunesan RF coil which is employedto excite the substanceunder test. The tuning apparatus includes a seriesof fixed value capacitors switched in the tuning circuit by controllable switches. A programmable controller is employedto control the switching and thereby the tuning of the coil.
5594339 FLEXIBLE NUCLEAR MAGNETIC RESONANCE RECEIVER COILS AND SYSTEMS HendersonRobert G; Kristoff James;Molyneaux David A Wickliffe, OH, UNITED STATES assignedto Picker
ALERT
International Inc A resonanceexciting coil disposedin an image region in which a main magneticfield and transversegradientshave beenproduced.A flexible receiving coil includesa flexible plastic sheeton which an electrically continuous flexible foil strip is adheredto receive signalsfrom the resonating nuclei. The coil alsoincludescomponents,mountedon the flexible plastic sheet, which may amplify the received signals before they are transmitted along a cable. A first soft material layer is mounted on the flexible plastic sheet for providing comfort to the patient. A flexible mechanical structure on which two flexible receiving coils adjustsan overlap betweenthe coils asthe coils are flexed to adjust interaction properties of the coils. Pivotal rods of a fixed length which connect two flexible coils causethe spacing of the coils to vary in accordanceto a flex applied to the coils to adjust the relative interactive properties with flexing. Flexible coils in modular components provide identification points on each modular component which connect to similar identification points on other flexible coil modular components.
5594340 APPARATUS FOR ACCURATELY CONTROLLING MOISTURE LEVELS OF AQUEOUS SURFACTANT COMPOSITIONS DURING ON LINE PROCESSING INCLUDING A CROSS-FEED PISTON ASSEMBLY Coyle Laurie; Finucane Kevin M; King James;Donoho Harold F; De Los SantosArmand North Arlington, NJ, UNITED STATES assignedto Lever Brothers Company Division of Conopco Inc An apparatusfor corring aqueoussurfactant composition and sampling moisture content wherein the apparatus includes a device for delivering composition to a main collection port; a device for coring the composition in the main collection port to form a sample; a device for delivering the sampleinto an NMR sensorarea; a device for measuringmoisture level of the sample in the NMR sensorarea; and a device for extracting the samplefrom the NMR sensorarea or returning the sampleto a main collection port which includes a cross feed piston assembly.
echo data output from the receiver on the Fourier space. Finally, the imaging apparatus has an input unit for adjusting a reference strength of the phase-encoding gradient magnetic field pulse so that echo data corresponding to spatial frequencies in the phase-encoding direction, which are the inverse and an integral multiple of a predetermined period of the periodic structure of the non-magnetic material in the phantom, is maximized.
ALERT
XXVII
apparatus wherein the amount of comparison operation processing of a bit allocator is minimized. A subband filter divides a PCM signal into and outputs a plurality of frequency subbands. A SMR calculator calculates, for each of the frequency subbands, an SMR which is a ratio between a signal level and a mask level. A bit allocator calculates a reference NMR which is a value obtained by subtracting, from an SMR of the entire frequency band, a S/N ratio calculated from a reference bit number to be allocated to one of the frequency subbands which exhibits a maximum SMR, and adjusts the reference NMR to perform bit allocation to the frequency subbands.
5587658 5594336
SHIMMING METHOD FOR NMR MAGNET USING UNSHIELDED GRADIENT SYSTEMS Sukumar STATES
Subramaniam Union City, CA, assigned to Bruker Instruments Inc
UNITED
An method for determining the inhomogeneities of the magnetic field of the magnet of an NMR system makes use of unshielded coils while minimizing the effect of eddy currents induced in the magnet components by the gradient fields. A first dataset is acquired by ramping the level of a gradient magnetic field to a maximum value and generating an RF pulse to excite the spins. After a delay time tl, a single data point is sampled. While the spins are allowed to relax, the gradient field magnitude is changed to the next level. Another RF pulse is generated and, after time t 1, the next data point is sampled. This process continues until a first complete dataset is acquired. The next gradient function is then applied in a similar manner, and the data points sampled after an RF pulse and a delay time of t2. During sampling of the second dataset, the gradient area for each spatial data point is equal to the gradient area for that spatial point during sampling of the first dataset. After the second dataset is acquired, a frequency distribution for the gradient direction is obtained using known techniques.
5588024
FREQUENCY
Takano Hidet Corporation The invention
SUBBAND APPARATUS Tokyo,
provides
JAPAN
a frequency
THREE POINT TECHNIQUE USING SPIN AND GRADIENT ECHOES FOR WATER/FAT SEPARATION
ENCODING
assigned
to NEC
subband
encoding
Gullapalli Rao P; Liu Haiying; Loncar Mark J Richmond Heights, OH, UNITED STATES assigned to Picker International Inc Magnetic resonance is excited in first and second species dipoles of a subject in a temporally constant magnetic field. The resonance is refocused to generate a spin echo centered at a time when the first and second species resonance signals are in-phase. Gradients echoes are generated, centered at a time (2n+l) pi/ delta omega before and after the spin echo, where delta omega is a difference between the first and second species resonance frequencies. In this manner, the first and second species signals are 180 degrees out-of-phase in the gradient echoes. The resonance is refocused one or more times to generate additional spin and gradient echoes with different phase encodings. The sequence is repeated with yet more phase encodings, and magnetic resonance signals from the spin echo and the two gradient echoes are reconstructed into a spin echo image (SO) and a pair of gradient echo images (s+ 1, s-l). A phase map is generated from the spin and gradient echo images. One of the gradient echo images is corrected with the phase map. The phase corrected gradient image is additively combined with the spin echo image to generate a first species image and is subtractively combined to generate a second species image.
5594337
LOCAL COIL FOR MAGNETIC RESONANCE ANGIOGRAPHY
XXVIII
Patents
Menomonee Falls, WI, UNITED Boskamp Eddy STATES assignedto Medical Advances Inc An angiographiccoil for performing blood flow studiesof
the large vesselsof the legs and lower pelvis employs an alternating series of coil elements having orthogonal sensitivities arrayed along a cover and basesurrounding the legs and lower pelvis and supported thereby. The alternatingcoil patternprovides good isolationbetweenthe coils in a coil that allows easy patient positioning. In a second embodiment, structures having conductors pass betweenthe legswhen the patient’slegsstraddle a divider of the coil form. The coil structure is open on sidesto permit easyentrance and exit from the coil by the patient. Multiple coils are usedto spanthe length of the elongate imaging area of the legs and a pre-amplifier network is employedto limit the inductancebetweenother coil and to provide for piecewiseimaging of the entire leg and pelvis region.
5594338 AUTOMATIC TUNING APPARATUS AND METHOD FOR SUBSTANCE DETECTION USING NUCLEAR QUADRUPOLE RESONANCE AND NUCLEAR MAGNETIC RESONANCE Magnuson Erik E Escondido, CA, UNITED STATES assignedto Quantum Magnetics Inc Apparatus for tuning a system for detecting a target substancethrough the useof nuclearquadrupoleresonance (NQR) or nuclear magnetic resonance (NMR). The apparatustunesan RF coil which is employedto excite the substanceunder test. The tuning apparatus includes a seriesof fixed value capacitors switched in the tuning circuit by controllable switches. A programmable controller is employedto control the switching and thereby the tuning of the coil.
5594339 FLEXIBLE NUCLEAR MAGNETIC RESONANCE RECEIVER COILS AND SYSTEMS HendersonRobert G; Kristoff James;Molyneaux David A Wickliffe, OH, UNITED STATES assignedto Picker
ALERT
International Inc A resonanceexciting coil disposedin an image region in which a main magneticfield and transversegradientshave beenproduced.A flexible receiving coil includesa flexible plastic sheeton which an electrically continuous flexible foil strip is adheredto receive signalsfrom the resonating nuclei. The coil alsoincludescomponents,mountedon the flexible plastic sheet, which may amplify the received signals before they are transmitted along a cable. A first soft material layer is mounted on the flexible plastic sheet for providing comfort to the patient. A flexible mechanical structure on which two flexible receiving coils adjustsan overlap betweenthe coils asthe coils are flexed to adjust interaction properties of the coils. Pivotal rods of a fixed length which connect two flexible coils causethe spacing of the coils to vary in accordanceto a flex applied to the coils to adjust the relative interactive properties with flexing. Flexible coils in modular components provide identification points on each modular component which connect to similar identification points on other flexible coil modular components.
5594340 APPARATUS FOR ACCURATELY CONTROLLING MOISTURE LEVELS OF AQUEOUS SURFACTANT COMPOSITIONS DURING ON LINE PROCESSING INCLUDING A CROSS-FEED PISTON ASSEMBLY Coyle Laurie; Finucane Kevin M; King James;Donoho Harold F; De Los SantosArmand North Arlington, NJ, UNITED STATES assignedto Lever Brothers Company Division of Conopco Inc An apparatusfor corring aqueoussurfactant composition and sampling moisture content wherein the apparatus includes a device for delivering composition to a main collection port; a device for coring the composition in the main collection port to form a sample; a device for delivering the sampleinto an NMR sensorarea; a device for measuringmoisture level of the sample in the NMR sensorarea; and a device for extracting the samplefrom the NMR sensorarea or returning the sampleto a main collection port which includes a cross feed piston assembly.