He Qing-yuan, Han Hong-bin, Xu Fang-jing-wei, Yan Jun-hao, Zeng Jin-jin, Li Xiao-gang, Fu Yu, Peng Yun, Chen He, Hou Chao, Xu Xiao-juan
Department of Radiology, Peking University Third Hospital, Beijing 100191, China.
Beijing Da Xue Xue Bao Yi Xue Ban. 2010 Apr 18;42(2):188-91.
To observe the diffusion of Gd-DTPA in brain extracellular space (ECS) by magnetic resonance imaging(MRI) and investigate the feasibility of ECS measurement by using MRI tracer method in vivo.
2 microL Gd-DTPA was introduced into ECS by caudate nucleus according to stereotaxic atlas in 8 Sprague Dawley(SD) rats (male, 280-320 g). The MRI scans were performed at 1 h, 3 h, 6 h, 9 h and 12 h respectively after administration. MRI appearances of Gd-DTPA diffusion and distribution was observed and compared. The MRI signal enhancement was measured at each time point. The neuroethology assessment was performed after MRI scanning at 12 h.
The injection was accurate at the center of the caudate nucleus in 6 rats, while, at the capsula externa in other 2 rats. Gd-DTPA diffused isotropically after it was introduced into caudate nucleus, which spread into lateral cortex at 3 h. The MRI signal enhancement distributed mainly in the middle cerebral artery territory. A significant difference was found between the signal enhancement ratio at 1 h and that at 3 h in the original point of caudate nucleus (t=95.63, P<0.01), and the signal enhancement attenuated following the exponential power function y=1.7886x(-0.1776) (R2=0.94). In 2 rats with the injection point at capsula externa, Gd-DTPA diffused anisotropically along the fiber track of white matter during 1 h to 3 h, and spread into the lateral cortex at 6 h.
The diffusion and clearance of Gd-DTPA in brain ECS could be monitored and measured quantitatively in vivo by MRI tracer method.
通过磁共振成像（MRI）观察钆喷酸葡胺（Gd-DTPA）在脑细胞外间隙（ECS）的扩散情况，并探讨MRI示踪剂法在体内测量ECS的可行性。
将8只雄性Sprague Dawley（SD）大鼠（体重280 - 320 g）按立体定位图谱经尾状核向ECS注入2 μL Gd-DTPA。给药后分别于1 h、3 h、6 h、9 h和12 h进行MRI扫描。观察并比较Gd-DTPA扩散和分布的MRI表现。测量各时间点的MRI信号增强情况。在12 h进行MRI扫描后进行神经行为学评估。
6只大鼠注射部位准确位于尾状核中心，另外2只位于外囊。Gd-DTPA注入尾状核后呈各向同性扩散，3 h时扩散至外侧皮质。MRI信号增强主要分布在大脑中动脉供血区。尾状核原注射点1 h与3 h的信号增强率有显著差异（t = 95.63，P < 0.01），信号增强呈指数幂函数y = 1.7886x（-0.1776）衰减（R2 = 0.94）。2只注射点在外囊的大鼠，Gd-DTPA在1 h至3 h沿白质纤维束各向异性扩散，6 h时扩散至外侧皮质。
MRI示踪剂法可在体内定量监测和测量Gd-DTPA在脑ECS中的扩散和清除情况。
