Anomalous transverse relaxation in 1H spectroscopy in human brain at 4 Tesla. - Archive ouverte HAL
Article Dans Une Revue Magnetic Resonance in Medicine Année : 1995

Anomalous transverse relaxation in 1H spectroscopy in human brain at 4 Tesla.

Résumé

Longitudinal (T1) and apparent transverse relaxation times (T2) of choline-containing compounds (Cho), creatine/phosphocreatine (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. T1-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 T2-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.

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Imagerie
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Dates et versions

hal-00349998 , version 1 (05-01-2009)

Identifiants

  • HAL Id : hal-00349998 , version 1
  • PUBMED : 7707916

Citer

S. Posse, C. A. Cuenod, R. Risinger, D. Le Bihan, R. S. Balaban. Anomalous transverse relaxation in 1H spectroscopy in human brain at 4 Tesla.. Magnetic Resonance in Medicine, 1995, 33 (2), pp.246-52. ⟨hal-00349998⟩
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