Human Brain Proton Metabolite Mapping at Short TE

短 TE 下的人脑质子代谢图谱

• 批准号: 6662532
• 负责人: GERALD B MATSON
• 金额: $ 34.09万
• 依托单位: NORTHERN CALIFORNIA INSTITUTE/RES/EDU
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-30 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6662532
• 关键词: brain disorder diagnosis; brain mapping; brain metabolism; clinical research; computer program /software; glutamates; glutathione; human subject; hydrogen ions; image processing; information systems; lasers; magnetic resonance imaging; mathematical model; measurement; nuclear magnetic resonance spectroscopy; protonation; statistics /biometry; technology /technique development

DESCRIPTION (provided by applicant): A major problem in quantification of proton metabolites obtained by high field magnetic resonance (MR) spectroscopic imaging (MRSI) at short TE is separating the metabolite resonances from the uneven and varying baseline Some of the baseline fluctuations are due to out-of-volume water and lipid signals, while other variations are due to the presence of macromolecules We propose a series of measures to improve the ability to separate metabolite and baseline signals, the most important of which involves obtaining a series of moderate signal-to noise (S/N) spectra at differing TE times with a sequence that includes closely spaced 180 degrees pulses (CP pulse train) to reduce J evolution for strongly coupled spins prior to acquisition This preserves the spectral patterns for strongly coupled resonances at the different TE values even though the signal amplitudes decay due to T2 relaxation Simultaneous fitting of the suite of spectra is expected to enable improved separation of metabolite signals from baseline, and to provide more reliable estimates of metabolite resonance areas A number of additional measures including 1) improved RF pulses, including improvement of hyperbolic secant pulses and a spin echo pulse cascade with immunity to B1 inhomogenicity for the CP pulse train, 2) improved methods of shimming, 3) improved MRSI acquisition sequences, 4) improved methods for processing of metabolite spectra, and 5) improvements for metabolite quantification in institutional units, based on coanalysis with tissue segmented structural MRI data, are planned Finally, a metabolite atlas of normal brain, reflecting regional metabolite levels and variations, will be developed This proposal is coordinated with the partner IRPG proposal for sharing of programs, pulses, data, and information to enhance the research at both sites.

描述（由申请人提供）： 通过短 TE 下的高场磁共振 (MR) 光谱成像 (MRSI) 获得的质子代谢物定量的一个主要问题是将代谢物共振与不均匀且变化的基线分开。一些基线波动是由于超量水造成的和脂质信号，而其他变化是由于大分子的存在造成的。我们提出了一系列措施来提高分离代谢物和基线信号的能力，其中最重要的是获得一系列中等信噪比不同 TE 时间的 (S/N) 谱，序列包括紧密间隔的 180 度脉冲（CP 脉冲序列），以减少采集前强耦合自旋的 J 演化 这保留了不同 TE 值下强耦合共振的谱图即使信号幅度由于 T2 弛豫而衰减，预计同时拟合这组光谱将能够改善代谢物信号与基线的分离，并提供更可靠的代谢物共振区域估计许多其他措施，包括 1)改进的射频脉冲，包括双曲正割脉冲和自旋回波脉冲级联的改进，对 CP 脉冲串的 B1 不均匀性具有免疫力，2) 改进的匀场方法，3) 改进的 MRSI 采集序列，4) 改进的代谢物谱处理方法，以及 5) 基于与组织分段结构 MRI 数据的协同分析，计划改进机构单位的代谢物量化。 最后，正常大脑的代谢物图谱，反映了区域该提案与合作伙伴 IRPG 提案相协调，以共享程序、豆类、数据和信息，以加强两个地点的研究。