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Experimental approaches to image localized human 31 P NMR spectroscopy
Author(s) -
Luyten Peter R.,
Groen Jan P.,
Vermeulen Jan W. A. H.,
Den Hollander Jan A.
Publication year - 1989
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910110102
Subject(s) - nuclear magnetic resonance spectroscopy , nuclear magnetic resonance , spectroscopy , chemistry , physics , quantum mechanics
Experimental procedures for obtaining localized 31 P NMR spectra of humans by means of the ISIS sequence are discussed in detail. The technique is optimized for use with volume coils and with surface coils in order to measure localized 31 P NMR spectra ofdifferent tissues and organs. Selective frequency‐modulated (FM) inversion and excitation pulses are applied for optimal inversion or excitation despite B1 inhomogeneity. Pulse imperfection may lead to spurious signal contributions from outside the selected volume; this contamination is reduced by using long pulse intervals, by properly ordering the ISIS acquisitions, and by using FM excitation pulses. Simultaneous measurement of multiple volumes was implemented by including an additional selective inversion pulse, and an extension of the ISIS addition/subtraction scheme. Localized T1 measurements with surface coils are implemented by using a B1‐insensitive inversion pulse in the inversion recovery sequence. The quantitative reproducibility of localized 31 P NMR spectra was verified. Absolute metabolite concentration can be determined after a suitable calibration of the 31 P NMR spectrum. Localized shimming is required to obtain localized 31 P NMR spectra of excellent spectral resolution. This is done by monitoring the 1 H NMR signal from water by a single‐shot localization technique. The techniques discussed can be applied to obtain spectra of brain, liver, heart, and other organs. 31 P NMR spectra of intracranial tumors demonstrate its applicability in the examination of patients. © 1989 Academic Press. Inc.