T2 relaxation effects on apparent N-acetylaspartate concentration in proton magnetic resonance studies of schizophrenia
T2 relaxation effects on apparent N-acetylaspartate concentration in proton magnetic resonance studies of schizophrenia
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DOI：
10.1016/j.pscychresns.2013.03.005
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发表时间：
2013-08-30
影响因子：
2.3
通讯作者：
Olson, David P.
中科院分区：
文献类型：
--
作者：
Bracken, Bethany K.;Rouse, Elizabeth D.;Olson, David P.
在过去的二十年中，许多磁共振波谱 (MRS) 研究报告称，与健康受试者相比，精神分裂症 (SZ) 患者关键大脑区域的 N-乙酰天冬氨酸 (NAA) 较低。少数研究报告 NAA 没有差异。许多方差来源可能导致这些不一致的结果，包括 SZ 受试者群体的异质性和方法学差异，例如 MRS 采集参数和采集后分析方法。当前的研究回顾了质子 MRS 文献，报告了深圳 NAA 的测量结果，重点是方法论。报告 NAA 较低的研究更有可能使用较长的回波时间 (TE)，而使用较短 TE 的研究报告没有浓度差异。这表明使用 MRS 进行的 NAA 定量受到 TE 选择的影响，并且已发表的 MRS 文献报道了使用长 TE 在 SZ 中进行 NAA 的分析，这与 SZ 组和健康对照组之间明显差异的 T-2 松弛效应相混淆。未来的 MRS 研究应该测量 T-2 弛豫时间。这将允许光谱浓度测量针对这些弛豫效应进行适当校正。此外，由于代谢物浓度和 T-2 弛豫时间是完全独立的变量，这可以提供有关感兴趣代谢物的不同信息。 (C) 2013 Elsevier Ireland Ltd. 保留所有权利。
Over the past two decades, many magnetic resonance spectroscopy (MRS) studies reported lower N-acetylaspartate (NAA) in key brain regions of patients with schizophrenia (SZ) compared to healthy subjects. A smaller number of studies report no difference in NAA. Many sources of variance may contribute to these discordant results including heterogeneity of the SZ subject populations and methodological differences such as MRS acquisition parameters, and post-acquisition analytic methods. The current study reviewed proton MRS literature reporting measurements of NAA in SZ with a focus on methodology. Studies which reported lower NAA were significantly more likely to have used longer echo times (TEs), while studies with shorter TEs reported no concentration difference. This suggests that NAA quantitation using MRS was affected by the choice of TE, and that published MRS literature reporting NAA in SZ using a long TE is confounded by apparent differential T-2 relaxation effects between SZ and healthy control groups. Future MRS studies should measure T-2 relaxation times. This would allow for spectral concentration measurements to be appropriately corrected for these relaxation effects. In addition, as metabolite concentration and T-2 relaxation times are completely independent variables, this could offer distinct information about the metabolite of interest. (C) 2013 Elsevier Ireland Ltd. All rights reserved.