Gerhalter Teresa, Carlier Pierre G, Marty Benjamin
Institute of Myology, NMR Laboratory, Paris, France
CEA, DRF, IBFJ, MIRCen, NMR Laboratory, Paris, France.
Physiol Rep. 2017 Aug;5(16). doi: 10.14814/phy2.13380.
In this article, we induced acute changes in extracellular volume fraction in skeletal muscle tissue and compared the sensitivity of a standard H T imaging method with different Na-NMR spectroscopy parameters within acquisition times compatible with clinical investigations. First, we analyzed the effect of a short ischemia on the sodium distribution in the skeletal muscle. Then, the lower leg of 21 healthy volunteers was scanned under different vascular filling conditions (vascular draining, filling, and normal condition) expected to modify exclusively the extracellular volume. The first experiment showed no change in the total sodium content during a 15 min ischemia, but the intracellular weighted Na signal slowly decreased. For the second part, significant variations of total sodium content, sodium distribution, and T and T2∗ of Na signal were observed between different vascular filling conditions. The measured sodium distribution correlates significantly with sodium T and with the short and long T2∗ fractions. In contrast, significant changes in the proton Tw signal were observed only in three muscles. Altogether, the mean Tw signal intensity of all muscles as well as their mean T did not vary significantly with the extracellular volume changes. In conclusion, at the expense of giving up spatial resolution, the proposed Na spectroscopic method proved to be more sensitive than standard H T approach to monitor acute extracellular compartment changes within muscle tissue.
在本文中，我们诱导骨骼肌组织细胞外体积分数发生急性变化，并在与临床研究兼容的采集时间内，比较了具有不同钠核磁共振波谱参数的标准HT成像方法的灵敏度。首先，我们分析了短暂缺血对骨骼肌中钠分布的影响。然后，对21名健康志愿者的小腿在不同血管充盈条件（血管引流、充盈和正常状态）下进行扫描，预期这些条件只会改变细胞外体积。第一个实验表明，在15分钟的缺血过程中，总钠含量没有变化，但细胞内加权钠信号缓慢下降。对于第二部分，在不同血管充盈条件下观察到总钠含量、钠分布以及钠信号的T和T2∗有显著变化。测得的钠分布与钠T以及短和长T2∗分数显著相关。相比之下，仅在三块肌肉中观察到质子Tw信号有显著变化。总体而言，所有肌肉的平均Tw信号强度及其平均T并未随细胞外体积变化而有显著差异。总之，在所提出的钠波谱方法中，尽管牺牲了空间分辨率，但在监测肌肉组织内急性细胞外间隙变化方面，它比标准HT方法更敏感。
