MR不同扩散敏感梯度方向纤维束成像的锰离子增强验证实验研究  

Validation of different gradients orientation diffusion tensor tractography of macaque monkeys with manganese-enhanced MR imaging

作　　者：张帆[1] 李坤成[1] 于春水[1] 常丽荣[2] 秦文[1] 卢光明[3] 

机构地区：[1]首都医科大学附属北京宣武医院放射科,100053 [2]首都医科大学解剖教研室 [3]南京军区南京总医院医学影像科

出　　处：《中华放射学杂志》2008年第10期1075-1079,共5页Chinese Journal of Radiology

基　　金：国家自然科学基金资助项目（30470519）;北京市科技新星资助项目（2005821）

摘　　要：目的以MR锰离子（Mn2＋）强化纤维束跟踪结果为标准，对恒河猴脑白质不同敏感梯度方向扩散张量纤维束成像（DTT）的结果进行验证。方法取7只成年雄性恒河猴，采集应用不同梯度场方向D1Tr。待数据采集完毕后，在猴脑额叶中央前回前肢运动中枢皮层内注射0．8mol的MnCl23μl，注射48h后获得三维MR Mn2＋强化的T1WI。在应用不同梯度场方向获取的扩散张量各向异性分数（FA）图上，依照皮层下脑白质Mn2＋强化的范围大小在对应层面选取纤维束跟踪的种子区，然后进行脑白质纤维束追踪，并将三维重组的脑白质纤维束投射到横断面FA图像上，对脑白质纤维束投射与T1WI上Mn2＋强化的部位、范围进行一致性对比分析。结果以Mn“纤维束跟踪结果作为标准，证实在使用纤维束追踪算法的条件下，采用不同扩散梯度编码方向重组的纤维束在中脑以上水平与Mn2＋强化结果在一侧纤维束跟踪中有一致性，从两者一致性评分结果来看，各组评分结果均为优和良，其中30和64个方向所得结果的评分最佳，7只均为优。中脑以下水平，不同扩散梯度编码方向重组的纤维束与M2＋纤维束跟踪结果有较大偏差。结论在使用纤维束追踪算法的条件下，扩散敏感梯度方向的取值不影响DTT纤维束跟踪结果，但Mn2＋增强验证结果证实，在中脑以下水平，DTT的纤维柬跟踪结果不可靠。Objective Using manganese enhanced MR imaging （ME-MRI） as a standard to validate the accuracy of white matter diffusion tensor tractography （DTT） with different gradients orientations in macaque monkeys. Methods Seven adult male macaque monkeys were scanned for DTY images with different number of gradients orientations. When all data were acquired, 3 μl of 0. 8 mol aqueous solution of MnCl2 was injected into the primary motor cortex representing forelimb for ME-MRI scanning 48 hours later. On the images of fractional anisotropy （ FA）, seed region for fiber tracking was chosen according to the subcortical enhanced range on ME-MRI, then the D33＂ fiber tracts projecting on axial images of FA were compared with enhancement region on T1WI of ME-MRI. Results Under the calculation method for fiber tracking in the study, different motion-probing gradients orientations led to results consistent with ME-MRI for the brain above the midbrain level. All group＇s concordance score of fibertracking results were good. Among them,30 and 64 orientation fiber tracking results were optimal. Below the midbrain level, there was significant difference between DTT fiber tracking and ME-MRI fiber tracking. Conclusion Different motion-probing gradients orientations do not influence DTI＂ fiber tracking. But below the midbrain level, the results of DTT fiber tracking were not reliable according to the standard results of ME-MRI fiber tracking.

关 键 词：磁共振成像 弥散 锰 恒河猴 

分 类 号：R686[医药卫生—骨科学]