正常成人前视路高分辨率弥散张量成像研究

High Resolution Diffusion Tensor Imaging of the Anterior Visual Pathway in Healthy Adults

的：检测健康成人前视路弥散张量成像（DTI）参数，探讨其分布特点及影响因素。方法：系列病例研究。选择2015年11月至2016年5月福州总医院体检中心参加体检的健康成人38例，应用3.0T MRI高分辨率弥散张量成像技术对其前视路进行扫描，测定前视路（左右侧视神经中点、视交叉正中点、左右侧视束中点）的各向异性分数（FA）、表观扩散系数（ADC）值，并用弥散张量纤维束成像（DTT）技术重建前视路纤维束，观察纤维束形态结构。采用Pearson相关性分析、两样本t检验及单因素方差分析对数据进行统计学分析。结果：DTI序列FA图、FA编码彩图及ADC图可分辨前视路的结构，DTT能追踪出具有3D效果的视交叉白质纤维束结构。视交叉中点FA、ADC值分别为0.491±0.075和（1.267±0.204）×10-3/mm2，两者呈负相关（r=-0.642，P 〈 0.00l）。前视路FA 、ADC值与性别和年龄均无相关性。前视路各部位FA、ADC值总体差异均有统计学意义（F=11.575，P 〈 0.001；F=5.024，P 〈 0.001），其中，视交叉处FA值最小（P 〈 0.001），ADC值最大（P 〈 0.001）。结论：健康成人前视路高分辨率DTI参数FA和ADC值敏感可靠。运用高分辨率DTI技术可满意显示变形较小的前视路纤维束结构，定量分析时应注意前视路不同位置的影响。

Objective： To measure diffusion tensor imaging （DTI） parameters in healthy adults and analyze the distribution characteristics and influencing factors. Methods： In this case-series study, high resolution diffusion tensor imaging was performed on the anterior visual pathway in 38 healthy adults at the physicalexamination center of Fuzhou General Hospital from November 2015 to May 2016 using 3.0T magnetic resonance imaging. The fractional anisotropy （FA） and apparent diffusion coefficient （ADC） values were measured on the anterior visual pathway, including the bilateral optic nerve center, midpoint of chiasma,and the midpoint of optic tract. The anterior visual pathway fiber bundle was reconstructed by diffusion tensor tracking （DTT） to observe the morphology of the anterior optic fiber bundle. Pearson correlation,independent samples t-test, and one-way analysis of variance were used to analyze the data. Results： The structure of the DTI sequence diagram of FA, FA color encoding, and ADC can distinguish the anterior visual pathway. DTT can be used to track with 3D effects the white matter fiber bundle structure of optic chiasma. The FA and ADC values of the midpoint of optic chiasma were 0.491±0.075, and 1.267±0.204×10-3/mm2. There was a significant negative correlation between FA and ADC （r=-0.642, P〈0.001）. FA and ADC values were independent of gender and age. Differences between FA and ADC in optic nerve, optic tract, or optic chiasma were significant （F=11.575, P〈0.001; F=5.024, P〈0.001）. The FA value was the smallest （P〈0.001） in the optic chiasma, and the ADC value was the largest at the same location （P〈0.001）. Conclusions： Highresolution DTI parameters FA and ADC are sensitive and reliable in the anterior visual pathway of healthy adults. The high resolution DTI technique can satisfactorily display small deformations of the anterior visual pathway fiber bundle structure. Attention should be paid to the influence of different positions of the anterior visual pathway in quantitative analyses.