Stanisz G J, Henkelman R M
Imaging Research, Sunnybrook Health Science Centre, University of Toronto, Ontario, Canada.
Magn Reson Med. 1998 Sep;40(3):405-10. doi: 10.1002/mrm.1910400310.
A diffusion-CPMG hybrid experiment was used to analyze the diffusion characteristics of different T2 relaxation components in bovine optic nerve. Data were collected using a pulsed field gradient (PFG) multi spin echo (MSE) CPMG sequence for parallel and perpendicular axon orientation and four diffusion times. The apparent diffusion coefficient (ADC) was evaluated for two observed T2 components as a function of axonal orientation and diffusion time delta. The short T2 component exhibited minor diffusional anisotropy and larger ADC, whereas the long T2 component showed significant anisotropy effects. This is consistent with the hypothesis that the short T2 component is associated with water within the myelin sheath, which is less restricted than axonal water that is limited by cell membrane permeability.
采用扩散-CPMG混合实验分析牛视神经中不同T2弛豫成分的扩散特性。使用脉冲场梯度（PFG）多自旋回波（MSE）CPMG序列，针对平行和垂直轴突方向以及四个扩散时间收集数据。针对两个观察到的T2成分，评估表观扩散系数（ADC）作为轴突方向和扩散时间增量的函数。短T2成分表现出较小的扩散各向异性和较大的ADC，而长T2成分则表现出显著的各向异性效应。这与以下假设一致：短T2成分与髓鞘内的水有关，其受限程度低于受细胞膜通透性限制的轴突内水。
