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Proton T 2 relaxation of cerebral metabolites of normal human brain over large TE range
Author(s) -
Brief E. E.,
Whittall K. P.,
Li D. K. B.,
MacKay A. L.
Publication year - 2005
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.916
Subject(s) - human brain , nuclear magnetic resonance , range (aeronautics) , chemistry , medicine , neuroscience , biology , materials science , physics , composite material
T 2 of NAA, creatine and choline‐containing compounds were measured in posterior frontal white matter and occipital grey matter in 10 healthy human volunteers. Decay curves comprised signals from eight TE times ranging from 30 to 800 ms with TR 2000 ms acquired with a PRESS sequence on a 1.5 T clinical scanner. Simulations were conducted to assess the precision of T 2 estimates from decay curves comprising varying numbers and ranges of TE points. Mean and standard errors for T 2 s of NAA, creatine and choline‐containing compounds were 300(8), 169(3) and 239(4) ms in posterior frontal white matter and 256(6), 159(8) and 249(8) ms in occipital grey matter. In vivo T 2 s found for choline and NAA were shorter than the T 2 s in the literature. The elevation of literature T 2 s is accounted for by the simulation results, which demonstrated that there is a bias towards lengthened T 2 s when T 2 is measured with a maximum TE ≈ T 2 . Concentration estimates are at risk of being underestimated if previously reported T 2 corrections are used. Copyright © 2004 John Wiley & Sons, Ltd.