Absolute metabolite quantification by in vivo NMR spectroscopy:: II.: A multicentre trial of protocols for in vivo localised proton studies of human brain
Absolute metabolite quantification by in vivo NMR spectroscopy:: II.: A multicentre trial of protocols for in vivo localised proton studies of human brain
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DOI：
10.1016/s0730-725x(98)00118-0
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发表时间：
1998-11-01
影响因子：
2.5
通讯作者：
Podo, F
中科院分区：
文献类型：
--
作者：
Keevil, SF;Barbiroli, B;Podo, F
我们进行了多中心试验，以评估使用体内质子核磁共振（NMR）的脑代谢物的绝对定量的三种技术的性能。所包括的技术是1）内水标准方法，2）基于体模替换的外标法，以及3）结合内标法和外标法元素以及脑水房室分析的更复杂方法。只有内部水标准技术可以很容易地在所有参与的地点实施，并提供了可接受的精度和实验室间的重现性。该方法对影响替代技术性能的许多实验因素不敏感，包括与负载、驻波和B-1不均匀性相关的影响;以及体模定位、用户专业知识和检查持续时间的实际问题。然而，内部水标准方法假定目标光谱体积内NMR可见水的浓度值。通常，有必要根据体积的灰质、白色质和脑脊液（CSF）含量以及灰质和白色质部分的核磁共振可见水含量来修改该假设浓度。结合来自11个研究中心的数据，健康受试者大脑中主要NMR可见代谢物的浓度（年龄范围20-35岁）使用内部水标准方法测定，（平均值+/- SD）：[NAA] = 10.0 +/- 3.4 mM（n = 53），[tCho] = 1.9 +/- 1.0 mM（n = 51），[Cr + PCr] = 6.5 +/- 3.7 mM（n = 51）。在一些参与的网站的系统不稳定性和其他来源的错误的证据加强了定量光谱的严格质量保证的必要性。(C)1998年爱思唯尔科学公司
We have performed a multicentre trial to assess the performance of three techniques for absolute quantification of cerebral metabolites using in vivo proton nuclear magnetic resonance (NMR). The techniques included were 1) an internal water standard method, 2) an external standard method based on phantom replacement, and 3) a more sophisticated method incorporating elements of both the internal and external standard approaches, together with compartmental analysis of brain water. Only the internal water standard technique could be readily implemented at all participating sites and gave acceptable precision and interlaboratory reproducibility. This method was insensitive to many of the experimental factors affecting the performance of the alternative techniques, including effects related to loading, standing waves and B-1 inhomogeneities; and practical issues of phantom positioning, user expertise and examination duration. However, the internal water standard method assumes a value for the concentration of NMR-visible water within the spectroscopic volume of interest. In general, it is necessary to modify this assumed concentration on the basis of the grey matter, white matter and cerebrospinal fluid (CSF) content of the volume, and the NMR-visible water content of the grey and white matter fractions. Combining data from 11 sites, the concentrations of the principal NMR-visible metabolites in the brains of healthy subjects (age range 20-35 years) determined using the internal water standard method were (mean +/- SD): [NAA] = 10.0 +/- 3.4 mM (n = 53), [tCho] = 1.9 +/- 1.0 mM (n = 51), [Cr + PCr] = 6.5 +/- 3.7 mM (n = 51). Evidence of system instability and other sources of error at some participating sites reinforces the need for rigorous quality assurance in quantitative spectroscopy. (C) 1998 Elsevier Science Inc.