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Proton T 2 relaxation study of water, N‐acetylaspartate, and creatine in human brain using Hahn and Carr‐Purcell spin echoes at 4T and 7T
Author(s) -
Michaeli Shalom,
Garwood Michael,
Zhu XiaoHong,
DelaBarre Lance,
Andersen Peter,
Adriany Gregor,
Merkle Hellmut,
Ugurbil Kamil,
Chen Wei
Publication year - 2002
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.10135
Subject(s) - phosphocreatine , nuclear magnetic resonance , dephasing , creatine , chemistry , relaxation (psychology) , spin echo , proton , carr , physics , condensed matter physics , magnetic resonance imaging , nuclear physics , energy metabolism , biology , medicine , ecology , biochemistry , radiology , endocrinology , neuroscience
Carr‐Purcell and Hahn spin‐echo (SE) measurements were used to estimate the apparent transverse relaxation time constant ( T † 2 ) of water and metabolites in human brain at 4T and 7T. A significant reduction in the T † 2values of proton resonances (water, N‐acetylaspartate, and creatine/phosphocreatine) was observed with increasing magnetic field strength and was attributed mainly to increased dynamic dephasing due to increased local susceptibility gradients. At high field, signal loss resulting from T † 2decay can be substantially reduced using a Carr‐Purcell‐type SE sequence. Magn Reson Med 47:629–633, 2002. © 2002 Wiley‐Liss, Inc.