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5309102 Frequency calibration for MRI scanner
New Patents
5309098 NUCLEAR MAGNETIC RESONANCE DETECTION OF GEOLOGIC STRUCTURES George R Coates, Melvin N Miller, Bouton assigned to Numar Corporation
John
An improved system for using nuclear magnetic resonance techniques to obtain information relating to geologic structures. The system of the present invention employs a variable sampling window which increases sampling efficiency by allowing the system to optimize the sampling interval, thereby maximizing the amount of data which can be obtained in a series of data samples.
xxv
A method and apparatus to reduce the noise in three-dimensional phase contrast magnetic resonance velocity measurements exploits the property that blood is incompressible and therefore the velocity field describing its flow must be divergence-free. The divergence-free condition can be incorporated by the projection operation on Hilbert space where the velocity measurements are projected onto the space of divergence-free velocity fields. The reduction of noise is achieved since the projection operation eliminates the noise component that is not divergence-free. Higher quality angiograms are produced due to the noise reduction in the velocity measurement signals.
5309101 5309099 METHOD OF DETERMINING REAL-TIME SPATIALLY LOCALIZED VELOCITY DISTRIBUTION USING MAGNETIC RESONANCE MEASUREMENTS Pabl Irarrazabal, Bob S Hu, Joh Pauly assigned to The Board of Trustees of the Leland Stanford Junior University Real-time spatially localized velocity distribution is measured using magnetic resonance techniques by first exciting a region of interest using an RF excitation pulse simultaneously with gradient pulses along two orthogonal axes. A cyclical read-out gradient is then applied along a read-out axis and a magnetic resonance signal is continuously sampled while the read-out gradient is applied. The excitation and read-out is repeated at time intervals to obtain time varying spatially localized velocities within the region of interest.
Jae K Kim, Donald B Plewes, Ross Henkelman, Toronto, Canada assigned to General Electric Company A method for MR imaging in an inhomogeneous magnetic field substantially without inhomogeneity induced artifacts is disclosed. The method includes acquiring more than one line of K-space per pulse sequence. The K-space data is acquired in partial line segments. The method allows shorter imaging times and higher image quality than conventional imaging methods for inhomogeneous fields.
5309102 FREQUENCY CALIBRATION MRI SCANNER
FOR
Todd W Deckard assigned to General Electric Company
5309100 FLOW MEASUREMENT INCOMPRESSIBLE FLUID DIVERGENCE-FREE CONSTRAINT
MAGNETIC RESONANCE IMAGING IN AN INHOMOGENEOUS MAGNETIC FIELD
OF USING
Samuel M Song, Sandy A Napel, Norbert J P& assigned to Board of Trustees of the Leland Stanford Junior University
An NMR scanner performs a prescan before each NMR scan sequence in which the optimal RF excitation frequency is automatically determined and applied to the scanner’s transceiver. The prescan sequence includes a pair of NMR measurements which provide data that allows the precise RF excitation frequency to be determined.
5309098 NUCLEAR MAGNETIC RESONANCE DETECTION OF GEOLOGIC STRUCTURES George R Coates, Melvin N Miller, Bouton assigned to Numar Corporation
John
An improved system for using nuclear magnetic resonance techniques to obtain information relating to geologic structures. The system of the present invention employs a variable sampling window which increases sampling efficiency by allowing the system to optimize the sampling interval, thereby maximizing the amount of data which can be obtained in a series of data samples.
xxv
A method and apparatus to reduce the noise in three-dimensional phase contrast magnetic resonance velocity measurements exploits the property that blood is incompressible and therefore the velocity field describing its flow must be divergence-free. The divergence-free condition can be incorporated by the projection operation on Hilbert space where the velocity measurements are projected onto the space of divergence-free velocity fields. The reduction of noise is achieved since the projection operation eliminates the noise component that is not divergence-free. Higher quality angiograms are produced due to the noise reduction in the velocity measurement signals.
5309101 5309099 METHOD OF DETERMINING REAL-TIME SPATIALLY LOCALIZED VELOCITY DISTRIBUTION USING MAGNETIC RESONANCE MEASUREMENTS Pabl Irarrazabal, Bob S Hu, Joh Pauly assigned to The Board of Trustees of the Leland Stanford Junior University Real-time spatially localized velocity distribution is measured using magnetic resonance techniques by first exciting a region of interest using an RF excitation pulse simultaneously with gradient pulses along two orthogonal axes. A cyclical read-out gradient is then applied along a read-out axis and a magnetic resonance signal is continuously sampled while the read-out gradient is applied. The excitation and read-out is repeated at time intervals to obtain time varying spatially localized velocities within the region of interest.
Jae K Kim, Donald B Plewes, Ross Henkelman, Toronto, Canada assigned to General Electric Company A method for MR imaging in an inhomogeneous magnetic field substantially without inhomogeneity induced artifacts is disclosed. The method includes acquiring more than one line of K-space per pulse sequence. The K-space data is acquired in partial line segments. The method allows shorter imaging times and higher image quality than conventional imaging methods for inhomogeneous fields.
5309102 FREQUENCY CALIBRATION MRI SCANNER
FOR
Todd W Deckard assigned to General Electric Company
5309100 FLOW MEASUREMENT INCOMPRESSIBLE FLUID DIVERGENCE-FREE CONSTRAINT
MAGNETIC RESONANCE IMAGING IN AN INHOMOGENEOUS MAGNETIC FIELD
OF USING
Samuel M Song, Sandy A Napel, Norbert J P& assigned to Board of Trustees of the Leland Stanford Junior University
An NMR scanner performs a prescan before each NMR scan sequence in which the optimal RF excitation frequency is automatically determined and applied to the scanner’s transceiver. The prescan sequence includes a pair of NMR measurements which provide data that allows the precise RF excitation frequency to be determined.