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Band‐selective spin echoes for in vivo localized 1 H NMR spectroscopy
Author(s) -
Shungu Dikoma C.,
Glickson Jerry D.
Publication year - 1994
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.1910320302
Subject(s) - homonuclear molecule , spins , spin echo , pulse sequence , nuclear magnetic resonance , chemistry , site directed spin labeling , spin (aerodynamics) , hyperpolarization (physics) , physics , nuclear magnetic resonance spectroscopy , electron paramagnetic resonance , condensed matter physics , magnetic resonance imaging , medicine , organic chemistry , molecule , radiology , thermodynamics
Abstract This study describes a new single spin‐echo spatial localization sequence, BASSALE or BAnd‐Selective Spin echo Acquisition for Localized Editing, that overcomes a number of the limitations of the STEAM and PRESS volume selection pulse sequences. It achieves conformal volume localization in a single shot by spatially tailored suppression of all magnetization outside a 2D region of interest followed by selection of a single orthogonal slice. This separation of spatial localization from the echo formation process has permitted use of a spectrally selective cosine‐modulated sinc refocusing pulse to acquire localized 1 H spectra with the water suppression efficiency of STEAM and the sensitivity of PRESS. Echoes formed by such spectrally selective pulses have been termed bandselective spin echoes. The BASSALE sequence attains shorter echo times than PRESS, inhibits scalar spin‐spin interactions to permit localized editing and T 2 relaxometry of metabolites with J‐coupled spins (e.g., lactate), is insensitive to homonuclear multiple‐quantum and polarization transfer effects, and can be made sensitive or insensitive to spin displacement effects. Applications are shown both with phantoms and in situ in the rat brain.