Development of a fast method for quantitative measurement of hyperpolarized 129Xe dynamics in mouse brain
Development of a fast method for quantitative measurement of hyperpolarized 129Xe dynamics in mouse brain
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DOI：
10.1002/nbm.1733
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发表时间：
2012-02-01
影响因子：
2.9
通讯作者：
Fujiwara, Hideaki
中科院分区：
文献类型：
--
作者：
Imai, Hirohiko;Kimura, Atsuomi;Fujiwara, Hideaki
建立了一种快速精确测量和定量测定超极化氙-129（Xe-129）在小鼠脑中动力学的方法。关键技术是基于重复施加射频（RF）脉冲，并在脑内多巴胺浓度因连续HP 129通气而达到稳定状态后测量HP 129磁化强度的降低。用一个简单的理论模型很好地描述了129核磁共振（NMR）信号的衰减。该技术使得能够快速评估速率常数α，其由脑血流量（CBF）、组织和血液之间的分配系数（lambda（i））和HP E129在脑组织中的纵向弛豫时间（T-1 i）组成，而没有RF脉冲的去极化和肺中的动力学的任何影响。该技术能够精确测定健康小鼠的α为0.103 +/- 0.018 s（-1）（+/- SD，n = 5）。为了研究该方法用于检测海人酸（KA）诱导的癫痫小鼠模型的脑中的生理变化的潜力，尝试跟踪KA注射后的时间过程。结果发现，α值随时间发生特征性变化，反映了KA注射诱导的脑生理状态的变化。通过同时用H-1磁共振成像和129脑血流动力学测量CBF并比较这些结果，提示除了KA诱发的癫痫引起的CBF增加外，T-1 i的减少可能是129脑血流动力学改变的原因。因此，本发明的方法将可用于检测脑中的病理生理状态，并为未来的脑研究提供新的工具。版权所有（C）2011约翰威利父子有限公司
A fast method has been established for the precise measurement and quantification of the dynamics of hyperpolarized (HP) xenon-129 (Xe-129) in the mouse brain. The key technique is based on repeatedly applying radio frequency (RF) pulses and measuring the decrease of HP Xe-129 magnetization after the brain Xe concentration has reached a steady state due to continuous HP Xe-129 ventilation. The signal decrease of the Xe-129 nuclear magnetic resonance (NMR) signal was well described by a simple theoretical model. The technique made it possible to rapidly evaluate the rate constant alpha, which is composed of cerebral blood flow (CBF), the partition coefficient of Xe between the tissue and blood (lambda(i)), and the longitudinal relaxation time (T-1i) of HP Xe-129 in the brain tissue, without any effect of depolarization by RF pulses and the dynamics in the lung. The technique enabled the precise determination of alpha as 0.103 +/- 0.018 s(-1) (+/- SD, n = 5) on healthy mice. To investigate the potential of this method for detecting physiological changes in the brain of a kainic acid (KA) -induced mouse model of epilepsy, an attempt was made to follow the time course of a after KA injection. It was found that the a value changes characteristically with time, reflecting the change in the physiological state of the brain induced by KA injection. By measuring CBF using H-1 MRI and Xe-129 dynamics simultaneously and comparing these results, it was suggested that the reduction of T-1i, in addition to the increase of CBF due to KA-induced epilepsy, are possible causes of the change in Xe-129 dynamics. Thus, the present method would be useful to detect a pathophysiological state in the brain and provide a novel tool for future brain study. Copyright (C) 2011 John Wiley & Sons, Ltd.