Field strength dependence of PRESS timings for simultaneous detection of glutamate and glutamine from 1.5 to 7 T

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• 作者：Jeff Snyder ; Alan Wilman
• 关键词：Glutamate ; Glutamine ; Magnetic resonance spectroscopy ; Spectral editing ; PRESS ; Strong coupling ; PRESS timings ; High field MRS
• 刊名：Journal of Magnetic Resonance
• 出版年：2010
• 出版时间：March 2010
• 年：2010
• 卷：203
• 期：1
• 页码：66-72
• 全文大小：585 K

文摘

An optimization of the PRESS sequence for magnetic resonance spectroscopy is presented to simultaneously detect the important brain metabolites of glutamate (Glu) and glutamine (Gln) at field strengths of 1.5, 3, 4.7, and 7 T. Standard, clinical examinations typically use short echo times which in general are not ideal for the separation of Glu and Gln. The optimization procedure is based on numerical product operator simulations to produce yield and overlap measurements for all possible practical choices of PRESS inter-echo timings. The simulations illustrate the substantial modulations in Glu and Gln with field strength. At all field strengths, the optimized timings demonstrate a significant reduction in overlap compared to short echo PRESS, while maintaining a high metabolite signal, with Glu and Gln yields >90 % when excluding T2 relaxation losses. Minimal overlap was attained at 7 T (0.3 % Gln contamination in the Glu signal), and 4.7 T (1.2 % ). The optimized timings were applied in vivo on healthy volunteers at field strengths of 1.5 and 4.7 T.