Fenyes D A, Narayana P A
University of Texas at Houston Medical School, Department of Radiology, 77030, USA.
Magn Reson Imaging. 1999 Jun;17(5):717-22. doi: 10.1016/s0730-725x(98)00220-3.
Complete apparent diffusion tensor (ADTs) of spinal cord was measured in vivo in nine rats at 2.0 T. Two rotationally invariant parameters, the trace, which is a measure of the mean diffusivity, and the lattice index (LI), which reflects the degree of orientation coherence of tissue, have been estimated from the ADT. The mean white matter (WM) trace value (3.05 +/- 0.26 mm2/sec) was found to be substantially higher than the gray matter (GM) trace (2.36 +/- 0.39 mm2/sec), in contrast with the published results on fixed, excised cord. Statistically significant anisotropic diffusion was observed in both WM and GM, with greater anisotropy in the WM (LI = 0.67 +/- 0.06) than in the GM (LI = 0.51 +/- 0.05).
在9只大鼠体内于2.0T磁场下测量了脊髓的完整表观扩散张量（ADT）。从ADT中估计了两个旋转不变参数，即作为平均扩散率度量的迹以及反映组织取向相干程度的晶格指数（LI）。发现白质（WM）的平均迹值（3.05±0.26平方毫米/秒）显著高于灰质（GM）的迹值（2.36±0.39平方毫米/秒），这与已发表的关于固定、切除脊髓的结果相反。在白质和灰质中均观察到具有统计学意义的各向异性扩散，白质中的各向异性（LI = 0.67±0.06）大于灰质中的各向异性（LI = 0.51±0.05）。
