Method for measuring the nuclear magnetic resonance (NMR) of substances having hyperpolarized nuclei using continuously refocused multiecho spectroscopic imaging

摘要

A nuclear magnetic resonance (NMR) method for spatially resolved measurement of the distribution of signals of metabolites of different resonance frequencies by application of a sequence of radio-frequency pulses and switched magnetic fields, wherein the generated signals are generated by application of read gradients in a spatially encoded manner in the direction of these gradients, is characterized in that, after a time interval TR/2, the initially excited magnetization is subjected to a sequence of several radio frequency pulses, which are equally spaced by time intervals TR, and the used magnetic field gradients in each TR interval are applied such that the originally excited magnetization is repeatedly refocused in several TR intervals and thereby read out several times, several signals are generated within one TR interval by multiple inversion of the read gradient, and the signals which are read-out several times are each identically spatially encoded by application of phase encoding gradients and therefore differ only with respect to dephasing given by the respective resonance frequency, such that the individual signals at any read-out time can subsequently be associated with the signal contributions of the examined substances of different resonance frequencies. This method permits chemical shift selective measurement of hyperpolarized metabolites.