Postmortem MRI of human brain hemispheres: T2 relaxation times during formaldehyde fixation.
Postmortem MRI of human brain hemispheres: T2 relaxation times during formaldehyde fixation.
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DOI：
10.1002/mrm.21909
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发表时间：
2009-04
影响因子：
3.3
通讯作者：
Arfanakis, Konstantinos
中科院分区：
文献类型：
--
作者：
Dawe, Robert J.;Bennett, David A.;Schneider, Julie A.;Vasireddi, Sunil K.;Arfanakis, Konstantinos
与体内成像不同，死后 MRI 允许在 MR 扫描后立即对组织样本进行侵入性检查。然而，自然组织分解和化学固定导致死后组织的 MRI 特性与体内发现的不同。此外，这些特性随着死后固定时间的流逝而变化。本研究的目的是表征在固定过程中尸体人脑半球随时间发生的 T2 松弛变化。死后三个月，每周对浸入甲醛溶液中的五个半球进行扫描，并在死后六个月再次扫描一次。测量整个半球的 T2 弛豫时间。随着时间的推移，死亡后半球边缘附近的T2值迅速下降，而深层组织的T2值下降得更慢。这种差异可能是由于距半球表面的距离相对较大，以及限制甲醛分子扩散到深层组织的其他障碍。此外，深层组织中的T2值并没有持续衰减至平台期，而是达到最小值，然后增加至平台期。最终的增加可能是由于组织分解时间延长的影响，这一假设得到了固定过程数值模拟的支持。
Unlike in vivo imaging, postmortem MRI allows for invasive examination of the tissue specimen immediately following the MR scan. However, natural tissue decomposition and chemical fixation cause the postmortem tissue’s MRI properties to be different from those found in vivo. Moreover, these properties change as postmortem fixation time elapses. The goal of this study was to characterize the T2 relaxation changes that occur over time in cadaveric human brain hemispheres during fixation. Five hemispheres immersed in formaldehyde solution were scanned on a weekly basis for three months postmortem, and once again at six months postmortem. The T2 relaxation times were measured throughout the hemispheres. Over time, T2 values near the edges of the hemispheres decreased rapidly after death, while T2 values of deep tissue decreased more slowly. This difference is likely due to the relatively large distance from the hemisphere surface, and other barriers limiting diffusion of formaldehyde molecules to deep tissues. In addition, T2 values in deep tissue did not continuously decay to a plateau, but instead reached a minimum and then increased to a plateau. This final increase may be due to the effects of prolonged tissue decomposition, a hypothesis that is supported by numerical simulations of the fixation process.
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影响因子：
3.3
作者：
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通讯作者：
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影响因子：
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