Christensen J D, Barrère B J, Boada F E, Vevea J M, Thulborn K R
Massachusetts General Hospital NMR Center, Dept. of Radiology, Charlestown, USA.
Magn Reson Med. 1996 Jul;36(1):83-9. doi: 10.1002/mrm.1910360115.
A quantitative in vivo method for obtaining maps of tissue sodium concentration (TSC) by MRI is compared to the invasive, global 22Na radionuclide dilutional technique in the normal rat brain. The MR method uses a three-dimensional projectional acquisition scheme to minimize signal losses from transverse relaxation. Internal calibration standards are used to convert the signal intensity into TSC after correction for B1 inhomogeneities by using the ratio of 23Na and 1H images obtained with identical B1 distributions and sensitivities at the two frequencies. Over the biological range of concentrations, the TSC, measured as the ratio of MR signals of 23Na and 1H, gives a linear response with concentration. In the normal rat brain, the mean TSC measured using the MRI method (TSC = 45 +/- 4 mM, animals = 5) is not significantly different from the global 22Na radionuclide method (TSC = 49 +/- 6 mM, animals = 7).
将一种通过磁共振成像（MRI）获取组织钠浓度（TSC）图谱的定量体内方法，与正常大鼠脑中侵入性的整体22Na放射性核素稀释技术进行比较。MR方法采用三维投影采集方案，以尽量减少横向弛豫导致的信号损失。在通过使用在两个频率下具有相同B1分布和灵敏度所获得的23Na和1H图像的比率对B1不均匀性进行校正之后，使用内部校准标准将信号强度转换为TSC。在浓度的生物学范围内，以23Na和1H的MR信号比率测量的TSC给出与浓度的线性响应。在正常大鼠脑中，使用MRI方法测量的平均TSC（TSC = 45 +/- 4 mM，动物数 = 5）与整体22Na放射性核素方法（TSC = 49 +/- 6 mM，动物数 = 7）无显著差异。
