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4525673 NMR spectrometer incorporating a re-entrant fifo
New Patents
A method for operating magnet correction coils is provided through the control of correction coil currents. The currents are determined from field measurements through the use of an iterative weighting algorithm. The algorithm is iterative and adjusts the weights at each iteration so as to reduce the range of variation.
4523596 BLOOD VESSEL PROJECTION IMAGING SYSTEM USING NUCLEAR MAGNETIC RESONANCE Albert Macovski e&r.
IX
back the most recently active word from its output register and re-store said word at a corresponding sequential position in the FIFO queue. To accommodate complex and interleaved control and data acquisition cycles, each FIFO word has a state portion for commanding external devices, a persistence portion for specifying the duration of selected state active in the FIFO output buffer for a desired persistence interval, and a repetition portion for specifying the number of consecutive discrete repetitions of the currently active state-persistence datum at the output of the FIFO. Termination of the cyclic sequence is accomplished at the expiration of a preselected number of complete cycles. The FIFO input address is selected automatically in accord with the number of words comprising a single complete sequence of instrument control/data acquisition functions.
4527124
A two-dimensional projection image of the NMR activity within a volume is obtained. The signals due to static material are‘cancelled and do not appear in the projection image. The signals due to moving blood in vessels produce an isolated image of the vessels with the superimposed structure removed.
METHOD OF AND DEVICE FOR DETERMINING A NUCLEAR MAGNETIZATION DISTRIBUTION IN A PART OF A BODY Comelis M J van Uijen, Eindhoven, Netherlands assigned to U S Philips Corporation
4525673 NMR SPECTROMETER INCORPORATING A REENTRANT FIFO Edward H Berkowitz assigned to Varian Associates Inc
Cyclic instrument control and data acquisition functions which are critically dependent upon synchrony are directed from a computer based system including a FIFO buffer adapted to feed-
The invention proposes a method and a device in which resonance signals (generated for NMR imaging) are sampled in the presence of a (semi-) static and a time modulated gradient magnetic field, the gradient direction of the fields applied being mutually perpendicular. The resonance signal is conditioned prior to the start of sampling. The sampled signals are associated with spatial frequencies (i.e. points in a spatial frequency space (kx, ky) which is the (2-D) Fourier transform of the actual (x, y) space), which are determined by the applied gradient fields. The (semi-) static gradient field always produces an increase (for example, in kx), while the time modulated gradient field always produces an image frequency which lies between two limits (ky and ky + ky). Consequently, the invention enables the determination of data in an entire
A method for operating magnet correction coils is provided through the control of correction coil currents. The currents are determined from field measurements through the use of an iterative weighting algorithm. The algorithm is iterative and adjusts the weights at each iteration so as to reduce the range of variation.
4523596 BLOOD VESSEL PROJECTION IMAGING SYSTEM USING NUCLEAR MAGNETIC RESONANCE Albert Macovski e&r.
IX
back the most recently active word from its output register and re-store said word at a corresponding sequential position in the FIFO queue. To accommodate complex and interleaved control and data acquisition cycles, each FIFO word has a state portion for commanding external devices, a persistence portion for specifying the duration of selected state active in the FIFO output buffer for a desired persistence interval, and a repetition portion for specifying the number of consecutive discrete repetitions of the currently active state-persistence datum at the output of the FIFO. Termination of the cyclic sequence is accomplished at the expiration of a preselected number of complete cycles. The FIFO input address is selected automatically in accord with the number of words comprising a single complete sequence of instrument control/data acquisition functions.
4527124
A two-dimensional projection image of the NMR activity within a volume is obtained. The signals due to static material are‘cancelled and do not appear in the projection image. The signals due to moving blood in vessels produce an isolated image of the vessels with the superimposed structure removed.
METHOD OF AND DEVICE FOR DETERMINING A NUCLEAR MAGNETIZATION DISTRIBUTION IN A PART OF A BODY Comelis M J van Uijen, Eindhoven, Netherlands assigned to U S Philips Corporation
4525673 NMR SPECTROMETER INCORPORATING A REENTRANT FIFO Edward H Berkowitz assigned to Varian Associates Inc
Cyclic instrument control and data acquisition functions which are critically dependent upon synchrony are directed from a computer based system including a FIFO buffer adapted to feed-
The invention proposes a method and a device in which resonance signals (generated for NMR imaging) are sampled in the presence of a (semi-) static and a time modulated gradient magnetic field, the gradient direction of the fields applied being mutually perpendicular. The resonance signal is conditioned prior to the start of sampling. The sampled signals are associated with spatial frequencies (i.e. points in a spatial frequency space (kx, ky) which is the (2-D) Fourier transform of the actual (x, y) space), which are determined by the applied gradient fields. The (semi-) static gradient field always produces an increase (for example, in kx), while the time modulated gradient field always produces an image frequency which lies between two limits (ky and ky + ky). Consequently, the invention enables the determination of data in an entire