Electricity: measuring and testing – Particle precession resonance – Using a nuclear resonance spectrometer system
Patent
1990-03-28
1992-03-24
Tokar, Michael J.
Electricity: measuring and testing
Particle precession resonance
Using a nuclear resonance spectrometer system
G01R 3320
Patent
active
050992074
ABSTRACT:
An MRI method for spectroscopy utilizes a sequence which includes four RF electromagnetic pulses (p1, p2, p3, p4), three of which are spatially selective to generate a resonance signal (e) from a sub-volume of an object. The phase difference between the first and the second 90.degree. excitation pulse amounts to 90.degree.. The waiting period (dt1) between the first and the second pulse (p1, p2) is chosen so that the second pulse (p2) selectively resets the nuclear spins excited by the first non-selective pulse (p1) in the longitudinal direction. The selectively reset magnetization, for example of fat, is recalled, after the dephasing of the non-reset magnetization, for example of water, by the further pulses (p3, p4). A spectrum is determined from the resonance signal (e). In a modified version in which the phases of the first and the second pulse are the same, the sequence is used for shimming a local field around the sub-volume.
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Slobod Jack D.
Tokar Michael J.
U.S. Philips Corp.
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