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Anomalous Transverse Relaxation in 1 H Spectroscopy in Human Brain at 4 Tesla
Author(s) -
Posse Stefan,
Cuenod Charles Andre,
Risinger Robert,
Bihan Denis Le,
Balaban Robert S.
Publication year - 1995
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.1910330215
Subject(s) - phosphocreatine , nuclear magnetic resonance , chemistry , relaxation (psychology) , creatine , nuclear magnetic resonance spectroscopy , pulse sequence , human brain , spin echo , in vivo magnetic resonance spectroscopy , pulse (music) , magnetic resonance imaging , physics , medicine , optics , biochemistry , detector , radiology , energy metabolism , psychiatry
Longitudinal ( T 1 ) and apparent transverse relaxation times ( T 2 ) of choline‐containing compounds (Cho), creatine/phospho‐creatine (Cr/PCr), and N‐acetyl aspartate (NAA) were measured in vivo in human brain at 4 Tesla. Measurements were performed using a water suppressed stimulated echo pulse sequence with complete outside volume presaturation to improve volume localization at short echo times. T 1 ‐values of Cho (1.2 ± 0.1 s), Cr (1.6 ± 0.3 s), and NAA (1.6 ± 0.2 s) at 4 Tesla in occipital brain were only slightly larger than those reported in the literature at 1.5 Tesla. Thus, TR will not adversely affect the expected enhancement of signal‐to‐noise at 4 Tesla. Surprisingly, apparent T 2 ‐values of Cho (142 ± 34 ms), Cr (140 ± 13 ms), and NAA (185 ± 24 ms) at 4 Tesla were significantly smaller than those at 1.5 Tesla and further decreased when increasing the mixing interval TM. Potential contributing factors, such as diffusion in local susceptibility related gradients, dipolar relaxation due to intracellular paramagnetic substances and motion effects are discussed. The results suggest that short echo time spectroscopy is advantageous to maintain signal to noise at 4 Tesla.