Electricity: measuring and testing – Particle precession resonance – Using a nuclear resonance spectrometer system
Patent
1993-05-12
1994-09-20
Tokar, Michael J.
Electricity: measuring and testing
Particle precession resonance
Using a nuclear resonance spectrometer system
G01R 3320
Patent
active
053492943
ABSTRACT:
A sequence controller (30) controls gradient pulse amplifiers (20) and a digital transmitter (24) to apply a conventional magnetic resonance imaging or spectroscopy sequence. One or more of the resonance excitation pulses includes a series of very small tip angle RF pulses (52, 70) applied in rapid succession substantially within the time interval of a normal RF excitation pulse (e.g. 10 msec.). A series of gradient pulses (58x, 58y, 72y, 72z) with linearly diminishing amplitudes and a repetition cycle that is an integer multiple of the duration of the very small tip angle RF pulses are applied such that an excitation trajectory in k-space follows a piecewise linear square spiral (FIG. 3 ) when gradients are applied along two axes or an octahedral spiral (FIG. 6 ) when a series of gradient pulses are applied along three axes. The subregion of resonance excitation is selectively shifted along one of the axes by applying a series of frequency offset pulses (66, 76) along one or more of the axes. In this manner, the position of the subregion of resonance excitation is shifted without changing the phase component of the RF pulses.
REFERENCES:
patent: 4793356 (1988-12-01), Misic et al.
patent: 4985677 (1991-01-01), Pauly
patent: 5025216 (1991-06-01), Pauly
patent: 5061897 (1991-10-01), Danby et al.
patent: 5105152 (1992-04-01), Pauly
patent: 5124651 (1992-06-01), Danby et al.
patent: 5235276 (1993-08-01), Lew
"Volume-Selective Excitation: A Novel Approach to Topical NMR", Aue, et al. J. Mag. Reson. vol. 56, pp. 350-354 (1984).
"A k-Space Analysis of Small-Tip-Angle Excitation", Pauly, et al., J. Mag. Reson. vol. 81, pp. 43-56 (1989).
"Correcting for Nonuniform k-Space Sampling in Two-Dimensional NMR Selective Excitation", Hardy, et al., J. Mag. Reson. vol. 87, pp. 639-645 (1990).
"New Spatial Localization Method Using Pulsed High-Order Field Gradients (SHOT: Selection with High-Order Gradient), " Oh, et al., Mag. Reson. in Medicine, vol. 18, pp. 63-70 (1991).
"A Three-Dimensional .pi. Pulse", Pauly, et al., SMRM Book of Abstracts, vol. 2, p. 493, (1991).
"Region of Interest Selection by Outer Volume Saturation", Crespigny, et al. (1989).
Picker International Inc.
Tokar Michael J.
LandOfFree
Two and three-dimensionally selective RF pulses for magnetic res does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Two and three-dimensionally selective RF pulses for magnetic res, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Two and three-dimensionally selective RF pulses for magnetic res will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2430219