Toward more reliable measurements of NOE effects in CEST spectra at around -1.6 ppm (NOE (-1.6)) in rat brain.
Toward more reliable measurements of NOE effects in CEST spectra at around -1.6 ppm (NOE (-1.6)) in rat brain.
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DOI：
10.1002/mrm.27370
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发表时间：
2019-01
影响因子：
3.3
通讯作者：
Zu Z
中科院分区：
文献类型：
--
作者：
Zu Z
最近，一些研究机构报道了一种新的在约-1.6ppm处的中继核奥弗豪泽增强（rNOE）饱和转移效应，称为NOE（-1.6），其在肿瘤和中风中的潜在应用。然而，NOE（-1.6）测量的可重复性令人担忧，因为许多其他出版物没有报道。本文旨在研究通常被忽视的实验设置对NOE（-1.6）信号的影响，并建立一个更可靠的测量NOE（-1.6）在9.4 T的框架。在大鼠脑中获得Z-光谱。进行拟合方法以量化除NOE（-1.6）之外的所有已知饱和转移效应。通过从Z-光谱中去除这些混杂效应获得残留信号，并用于定量NOE（-1.6）。采用多层面成像技术研究NOE（-1.6）对脑区的依赖性。还评价了安乐死、麻醉、呼吸气体和RF辐照功率的影响。结果表明，NOE（-1.6）由于例如直接水饱和（DS）效应，在相对高的照射功率下，在原始Z光谱中通常不能清楚地观察到信号贡献，但是在去除其他非特异性效应之后可以可视化;此外，NOE（-1.6）效应取决于脑区，死后降低，长时间麻醉后转移，并可通过增加O2和N2 O呼吸空气浓度来增强。由于NOE（-1.6）效应比其他CEST效应更易受DS效应的影响，对生理条件更敏感，因此有必要将已知的敏感性纳入实验设计和数据分析，以确保更可靠的NOE（-1.6）结果。
Recently, a new relayed nuclear Overhauser enhancement (rNOE) saturation transfer effect at around -1.6 ppm, termed NOE(-1.6), and its potential applications in tumor and stroke were reported by several institutes. However, there is a concern of the reproducibility of NOE(-1.6) measurements since it is not reported by many other publications. This paper aims to study the influence of typically overlooked experimental settings on the NOE(-1.6) signal, and to build a framework for more reliable measurements of NOE(-1.6) at 9.4 T. Z-spectra were obtained in rat brains. A fitting approach was performed to quantify all known saturation transfer effects except NOE(-1.6). Residual signals were obtained by removing these confounding effects from Z-spectra and used to quantify NOE(-1.6). Multiple-slice imaging was performed to study the NOE(-1.6) dependence on brain regions. The influence of euthanasia, anesthesia, breathing gases, and RF irradiation power was also evaluated. Results demonstrate that the NOE(-1.6) signal contributions are often not clearly observable in raw Z-spectra at relatively high irradiation powers due to e.g. the direct water saturation (DS) effect, but can be visualized after removing other non-specific effects; also, the NOE(-1.6) effect depends on brain region, decreases postmortem, shifts after long-duration anesthesia, and may be enhanced by increasing O2 and N2O breathing air concentrations. Since the NOE(-1.6) effect is more susceptible to the DS effect and more sensitive to physiological conditions than are other CEST effects, incorporating known sensitivities into the experimental design and data analysis is necessary to ensure more reliable NOE(-1.6) results.
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影响因子：
3.3
作者：
Jones, Craig K.;Polders, Daniel;Hua, Jun;Zhu, He;Hoogduin, Hans J.;Zhou, Jinyuan;Luijten, Peter;van Zijl, Peter C. M.
通讯作者：
van Zijl, Peter C. M.
影响因子：
3.3
作者：
Zhang XY;Wang F;Jin T;Xu J;Xie J;Gochberg DF;Gore JC;Zu Z
通讯作者：
Zu Z
影响因子：
2.5
作者：
Gore JC;Zu Z;Wang P;Li H;Xu J;Dortch R;Gochberg DF
通讯作者：
Gochberg DF
来自Z频谱拟合的2ppm（CEST@2ppm）处的CEST信号与脑肿瘤中的肌酸分布相关。
影响因子：
2.9
作者：
Cai, Kejia;Singh, Anup;Poptani, Harish;Li, Weiguo;Yang, Shaolin;Lu, Yang;Hariharan, Hari;Zhou, Xiaohong J.;Reddy, Ravinder
通讯作者：
Reddy, Ravinder
影响因子：
3.3
作者：
Heo HY;Zhang Y;Jiang S;Lee DH;Zhou J
通讯作者：
Zhou J