关键词: 磁共振成像, 三维重建, 脑干, 交叉纤维 

Abstract:

Objective　 To investigate the features of decussation of the superior cerebellar peduncle(SCP) by diffusion tensor imaging(DTI) and diffusion tensor tractography(DTT) on 3.0T MR.　Methods　Twenty healthy volunteers were examined on SIEMENS 3.0T MRI diffusion tensor imaging (DTI) (b0=0 s/mm2, b1 =1000 s/mm2) ; post processing were made in SIEMENS Leonardo workstation using SIEMENS Standard 6 directions software to reconstruct the white matter fibers with fractional anisotropy (FA) threshold value 0.08, angle threshold value 80°and voxel size 1.2 mm×1.2 mm×3 mm. The FA of decussation of SCP was compared with that of the fiber of SCP by paired t-test.　Results　 There were three kinds of MR fiber tracking appearances at decussation of SCP of brainstem on MRI diffusion tensor tractography(DTT). Decussation of SCP of 20 cases was classified as follows: ①crossing fiber, accounting for 65% (13 cases); ②＞＜ kissing fiber, accounting for 25% (5 cases); ③ Y forking fiber, accounting for 10% (2 cases). There was  statistically significant difference in FA value (t=7.22, 0.40±0.13 and 0.65±0.08，P＜0.05) between decussation of SCP and that of the fiber of SCP. Conclusions　3.0T MR would be a useful technology for demonstrating the anatomic features of decussation of SCP of the brainstem, while DTT 3D-reconstruction is valuable for demonstrating the distribution of the crossing fibers in the brainstem during clinical application.

Key words: Magnetic resonance imaging, Three-dimensional reconstruction, Brain stem, Crossing fiber