Biological aspects of sodium-23 imaging.
Biological aspects of sodium-23 imaging.
复制标题
钠 23 成像的生物学方面。
DOI：
10.1093/oxfordjournals.bmb.a071964
复制
发表时间：
1984
影响因子：
6.7
通讯作者：
Hilal,SK
中科院分区：
文献类型：
--
作者：
Maudsley,AA;Hilal,SK
钠是活体组织中第二丰富的核磁共振可观察核，仅次于质子。它以 160mM 的浓度存在于细胞外空间中，并被 ATP 驱动的钠钾泵从活细胞内高度排除，从而使细胞内浓度约为 12mM 至 20mM。脑组织中的平均总钠浓度为 50 mM。病理变化，如组织损伤、水肿或坏死，导致细胞外间隙扩大或钠泵受损，会导致组织中总钠浓度增加。板 IV：A 说明了对于大脑内某些异常情况，钠的 NMR 观察结果与质子或水浓度的预期变化相比的预期变化。首先，脑脊液（CSF）中的钠浓度为160mM，水浓度为99%，而灰质中的钠浓度为84%，白质中的水浓度为70%，钠成像的正常大脑和心室之间的图像对比度高于质子成像。其次，在单纯性水肿中，组织总水分大约增加 10%，代表细胞外室增加 50%。因此，组织钠总量将增加近 25%，并且组织钠的相对变化大于水的相对变化。第三，在细胞死亡或组织坏死的情况下，钠泵崩溃，钠进入细胞。据观察，钠浓度的增加高达 300%-400%'-2，而水含量的增加约为 12%，3 提供了钠浓度比质子浓度大得多的对比度。最后，就肿瘤而言，整个肿瘤区域和周围水肿的水浓度会发生 10%—15% 的变化。对于钠，人们预计会看到几个区域，从简单的水肿开始，然后是非坏死肿瘤，由于细胞外室较小，钠浓度可能较低，最后中央坏死区域将显示钠的急剧增加。
Sodium is the second most abundant NMR-observable nucleus in living tissue, following protons. It is present in the extracellular space at a concentration of 160mM and is excluded to a high degree from within the living cell by the ATP-driven sodium-potassium pump giving an intracellular concentration of approximately 12mM to 20 mM. The average total sodium concentration in brain tissue is 50 mM. Pathologic changes, such as tissue injury, oedema or necrosis, which result in an expansion of the extracellular space or impairment of the sodium pump will result in an increase of total sodium concentration in tissue. Plate IV: A illustrates the changes expected for the NMR observation of sodium in comparison with that expected for proton, or water concentration, for certain abnormal conditions within the brain. Firstly, with a sodium concentration of 160mM in cerebrospinal fluid (CSF) and a water concentration of 99% in comparison with 84% in grey matter and 70% in white matter, the image contrast between normal brain and ventricles is higher with sodium imaging than proton imaging. Secondly, in simple oedema there is approximately a 10% increase in total tissue water, representing a 50% increase in the extracellular compartment. The total tissue sodium will therefore increase by almost 25% and the relative change in tissue sodium is greater than for water. Thirdly, in the case of cell death or tissue necrosis, the sodium pump breaks down and sodium enters the cell. The increase in sodium concentration has been observed to be as much as 300%-400%'-2 while the increase of water content is about 12%, 3 providing a much larger contrast for sodium concentration than for protons. Finally, in the case of neoplasms, there is a 10%—15% change in water concentration over the entire field of the tumour and the surrounding oedema. With sodium, one would expect to see several zones starting with simple oedema, followed by the non-necrotic tumour which may have lower sodium concentration due to the smaller extracellular compartment, and finally the central necrotic region will show a dramatic increase of sodium.