Characterization of the NMR behavior of white matter in bovine brain
Characterization of the NMR behavior of white matter in bovine brain
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DOI：
10.1002/mrm.20680
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发表时间：
2005-11-01
影响因子：
3.3
通讯作者：
MacKay, AL
中科院分区：
文献类型：
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作者：
Bjarnason, TA;Vavasour, IM;MacKay, AL
在24℃和37℃的H-1-核磁共振谱仪上对来自5个牛脑的15个白质样品进行了体外实验，24℃和37℃的样品的平均髓鞘水组分(MWF)分别为10.9%和11.8%。在37*C下的T_1驰豫时间为830毫秒，表现为单指数行为。提出了一个包含细胞内/外(IE)水、髓鞘水、非髓鞘组织和髓鞘组织的四池模型来模拟牛白质的核磁共振行为。引入了交叉松弛校正，以补偿测量数据点的移动和由于交叉松弛而导致的Carr-Purcelf-Meiom-Gill(CPMG)测量期间的T-2倍。这一修正被发现是轻微的，提供了使用多ECHO技术测量的MWF接近物理值的证据。在24℃时，髓鞘组织与髓鞘水、髓鞘水与IE水、IE水与非髓鞘组织之间的交叉松弛时间分别约为227、2064和402ms。在37℃时，这些相同的交叉松弛时间分别为158、1021和170毫秒。37℃时，髓鞘水与髓鞘的交换率为11.8 S(-1)，IE水与非髓鞘组织的交换率为6.8 S(-1)。这些交换率具有相似的大小，这表明IE水与非髓鞘组织之间的相互作用不容忽视。医学杂志54：1072-1081,2005。(C)2005年Wiley-Liss，Inc.
In vitro experiments on 15 white matter samples from five bovine brains were performed on a H-1-NMR spectrometer at 24 degrees C and 37 degrees C. The average myelin water fractions (MWFs) were 10.9% and 11.8% for samples at 24 degrees C and 37 degrees C, respectively. The T, relaxation time at 37*C was found to be 830 ms, exhibiting monoexponential behavior. A four-pool model including intra/extracellular (IE) water, myelin water, nonmyelin tissue, and myelin tissue was proposed to simulate the NMR behavior of bovine white matter. A cross-relaxation correction was introduced to compensate for shifting of the measured data points and T-2 times over the duration of the Carr-Purcelf-Meiboom-Gill (CPMG) measurement due to cross relaxation. This correction was found to be slight, providing evidence that MWFs measured using a multiecho technique are near physical values. At 24 degrees C the cross-relaxation times between myelin tissue and myelin water, myelin water and IE water, and IE water and nonmyelin tissue were found to be approximately 227, 2064, and 402 ms, respectively. At 37 degrees C these same cross-relaxation times were 158, 1021, and 170 ms, respectively. The exchange rate between myelin water and myelin was found to be 11.8 s(-1) at 37 degrees C, while the exchange rate between IE water and nonmyelin tissue was found to be 6.8 s(-1). These exchange rates are of similar magnitude, which indicates that the interaction between IE water and nonmyelin tissue cannot be ignored. Magn Reson Med 54:1072-1081, 2005. (c) 2005 Wiley-Liss, Inc.