OBJECT: A novel method of estimating metabolite T1 relaxation times using MR spectroscopic imaging (MRSI) is proposed. As opposed to conventional single-voxel metabolite T1 estimation methods, this method investigates regional and gray matter (GM)/white matter (WM) differences in metabolite T1 by taking advantage of the spatial distribution information provided by MRSI. MATERIAL AND METHODS: The method, validated by Monte Carlo studies, involves a voxel averaging to preserve the GM/WM distribution, a non-linear least squares fit of the metabolite T1 and an estimation of its standard error by bootstrapping. It was applied in vivo to estimate the T1 of N-acetyl compounds (NAA), choline, creatine and myo-inositol in eight normal volunteers, at 1.5 T, using a short echo time 2D-MRSI slice located above the ventricles. RESULTS: WM-T 1,NAA was significantly (P < 0.05) longer in anterior regions compared to posterior regions of the brain. The anterior region showed a trend of a longer WM T1 compared to GM for NAA, creatine and myo-Inositol. Lastly, accounting for the bootstrapped standard error estimate in a group mean T1 calculation yielded a more accurate T1 estimation. CONCLUSION: The method successfully measured in vivo metabolite T1 using MRSI and can now be applied to diseased brain.
OBJECT: A novel method of estimating metabolite T1 relaxation times using MR spectroscopic imaging (MRSI) is proposed. As opposed to conventional single-voxel metabolite T1 estimation methods, this method investigates regional and gray matter (GM)/white matter (WM) differences in metabolite T1 by taking advantage of the spatial distribution information provided by MRSI. MATERIAL AND METHODS: The method, validated by Monte Carlo studies, involves a voxel averaging to preserve the GM/WM distribution, a non-linear least squares fit of the metabolite T1 and an estimation of its standard error by bootstrapping. It was applied in vivo to estimate the T1 of N-acetyl compounds (NAA), choline, creatine and myo-inositol in eight normal volunteers, at 1.5 T, using a short echo time 2D-MRSI slice located above the ventricles. RESULTS: WM-T 1,NAA was significantly (P < 0.05) longer in anterior regions compared to posterior regions of the brain. The anterior region showed a trend of a longer WM T1 compared to GM for NAA, creatine and myo-Inositol. Lastly, accounting for the bootstrapped standard error estimate in a group mean T1 calculation yielded a more accurate T1 estimation. CONCLUSION: The method successfully measured in vivo metabolite T1 using MRSI and can now be applied to diseased brain.
Authors: A A Maudsley; A Darkazanli; J R Alger; L O Hall; N Schuff; C Studholme; Y Yu; A Ebel; A Frew; D Goldgof; Y Gu; R Pagare; F Rousseau; K Sivasankaran; B J Soher; P Weber; K Young; X Zhu Journal: NMR Biomed Date: 2006-06 Impact factor: 4.044
Authors: Radhika Srinivasan; Charles Cunningham; Albert Chen; Daniel Vigneron; Ralph Hurd; Sarah Nelson; Daniel Pelletier Journal: Neuroimage Date: 2006-01-23 Impact factor: 6.556
Authors: Carmen M Cirstea; William M Brooks; Sorin C Craciunas; Elena A Popescu; In-Young Choi; Phil Lee; Ali Bani-Ahmed; Hung-Wen Yeh; Cary R Savage; Leonardo G Cohen; Randolph J Nudo Journal: Stroke Date: 2011-02-17 Impact factor: 7.914
Authors: Sergio E Baranzini; Radhika Srinivasan; Pouya Khankhanian; Darin T Okuda; Sarah J Nelson; Paul M Matthews; Stephen L Hauser; Jorge R Oksenberg; Daniel Pelletier Journal: Brain Date: 2010-09 Impact factor: 13.501
Authors: D T Okuda; R Srinivasan; J R Oksenberg; D S Goodin; S E Baranzini; A Beheshtian; E Waubant; S S Zamvil; D Leppert; P Qualley; R Lincoln; R Gomez; S Caillier; M George; J Wang; S J Nelson; B A C Cree; S L Hauser; D Pelletier Journal: Brain Date: 2008-11-20 Impact factor: 13.501