正常视神经MR扩散张量成像扫描参数初步研究

目的：探讨视神经MR扩散张量成像最佳的扫描参数，获得最佳的图像质量。方法：采用GE Signa Twin1．5T超导磁共振扫描仪，头颅8通道相控阵线圈，单次激发ZOOM自旋回波平面成像序列，选择30例正常成人志愿者，随机分为三组，使用不同的扩散敏感梯度方向数、b值和层厚／层间距，对视神经进行MR扩散张量成像研究。将扩散张量成像原始数据输入个人计算机，应用Volume-one 1．72软件进行后处理。结果：扩散敏感梯度方向数为13个方向、b值1000s／mm^2、层厚／层间距为3／0mm的扫描参数，可以获得高质量的视神经扩散张量图像，图像清晰，信躁比高，无明显伪影及扭曲、变形。结论：本研究初步建立了视神经最佳的磁共振扩散张量成像扫描参数，获得的图像清晰，能够满足临床研究和应用的需要。

The preliminary study on scanning parameters of MR diffusion tensor imaging in normal optic nerve

Objective：To search for the optimal scanning parameters for MR diffusion tensor imaging in tile study of tile optic nerve. Methods：Images were acquired with a 1.5 T GE Signa Twin MR scanner with 8-clannel head phased array coil using a single-shot zonal oblique muhislice echoplanar imaging （ZOOM-EPI）. 30 cases of healthy volunteers who were divided three groups randomly were studied with using different diffusion-sensitive gradient directions, b value, and slice tificlaless/interval. Primary data of diffusion tensor imaging were processed off-line in file personal computer, with the post-processing software of the Volume-one 1.72.Results：When the parame- ters of MR-DTI sequence were 13 directions of diffnsion-sensitive gradients, 1000 s/mm2 of b value and 3/0 nun of tlfiekness/interval paralleling optic nerve scanning, the high quality DT images of directionally encoded color（DEC） maps and fractional anisotropy （FA） maps were acquired with high MR signal-to-noise ratio（SNR） and minimized partial volume effects and motion artifacts such as distortion or deformation of optic nerve. Conclusion：The optimal parameters of optic nerve for MR diffusion tensor imaging （MR-DTI） scanning are established preliminarily in the study. The DTI maps of optic nerve could satisfy the needs of clinical researching and applications.