On the use of Cramer-Rao minimum variance bounds for the design of magnetic resonance spectroscopy experiments
On the use of Cramer-Rao minimum variance bounds for the design of magnetic resonance spectroscopy experiments
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DOI：
10.1016/j.neuroimage.2013.07.062
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发表时间：
2013-12-01
期刊：
影响因子：
5.7
通讯作者：
Kreis, Roland
中科院分区：
文献类型：
--
作者：
Bolliger, Christine S.;Boesch, Chris;Kreis, Roland
局域磁共振波谱(MRS)在临床脑研究中得到了广泛的应用。获得一维光谱的标准采集序列受到来自许多代谢物的光谱贡献的大量重叠的影响。因此，应用专门调谐的编辑序列或二维获取方案来扩展信息内容。调整特定的采集参数可以使序列对某些目标代谢物更有效或更具体。Cramer-Rao界已被用于其他领域的实验优化，现在被证明是非常有用的设计准则，用于局部化MRS序列优化。对一维和二维MRS的原理进行了说明，特别是2D分离实验，在该实验中可以取消通常对等距离回波时间间隔和每回波时间相等采集时间的限制。特别强调了对GABA和谷氨酸的定量实验的优化。基本原理通过蒙特卡罗模拟和活体实验得到验证，重复获取来自健康受试者的广义二维分离脑谱，并通过Bootstrapping扩展以更好地定义量化不确定度。(C)2013 Elsevier Inc.保留所有权利。
Localized Magnetic Resonance Spectroscopy (MRS) is in widespread use for clinical brain research. Standard acquisition sequences to obtain one-dimensional spectra suffer from substantial overlap of spectral contributions from many metabolites. Therefore, specially tuned editing sequences or two-dimensional acquisition schemes are applied to extend the information content. Tuning specific acquisition parameters allows to make the sequences more efficient or more specific for certain target metabolites. Cramer-Rao bounds have been used in other fields for optimization of experiments and are now shown to be very useful as design criteria for localized MRS sequence optimization. The principle is illustrated for one- and two-dimensional MRS, in particular the 2D separation experiment, where the usual restriction to equidistant echo time spacings and equal acquisition times per echo time can be abolished. Particular emphasis is placed on optimizing experiments for quantification of GABA and glutamate. The basic principles are verified by Monte Carlo simulations and in vivo for repeated acquisitions of generalized two-dimensional separation brain spectra obtained from healthy subjects and expanded by bootstrapping for better definition of the quantification uncertainties.(C) 2013 Elsevier Inc. All rights reserved.