Axial diffusivity is increased in the degenerating superior cerebellar peduncles of Friedreich's ataxia
Axial diffusivity is increased in the degenerating superior cerebellar peduncles of Friedreich's ataxia
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DOI：
10.1007/s00234-010-0807-1
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发表时间：
2011-05-01
期刊：
影响因子：
2.8
通讯作者：
Mascalchi, Mario
中科院分区：
文献类型：
--
作者：
Della Nave, Riccardo;Ginestroni, Andrea;Mascalchi, Mario
扩散张量磁共振成像 (DTI) 证明白质 (WM) 损伤区域的分数各向异性 (FA) 降低通常与径向扩散率增加相关，而据报道轴向扩散率降低、不变或增加。为了更好地定义典型人类神经退行性疾病中发生的轴向扩散率变化的类型，我们研究了弗里德赖希共济失调 (FRDA) 的轴向和径向扩散率，其特征是齿状核的选择性神经元丢失和萎缩以及小脑上脚 (SCP) 的 FA 减少。 在 14 名 FRDA 患者和 14 名健康人中评估了全脑 WM 的轴向和径向扩散率志愿者使用 1.5 T 的 DTI 和基于束的空间统计 (TBSS) 方法（FSL 软件的一部分）。TBSS 分析显示中脑中央的单个区域对应于 SCP 的交叉，该区域在患者中表现出比对照组低的 FA。在该区域中，观察到轴向和径向扩散率显着增加。没有观察到轴向扩散率显着降低的簇，而整个大脑中存在径向扩散率增加的额外簇。反映慢性 WM 束损伤的 FRDA 患者 SCP 中 FA 的选择性减少与轴向和径向扩散率的增加相关，后者比前者更明显。慢性退化的 WM 束中轴向扩散率增加的超微结构和生物物理基础值得进一步研究。
Decreased fractional anisotropy (FA) demonstrated by diffusion tensor MR imaging (DTI) in areas of white matter (WM) damage is generally associated with increase of radial diffusivity, while axial diffusivity is reported to be decreased, unchanged, or increased. Aiming to better define the type of axial diffusivity change occurring in a typical human neurodegenerative disease, we investigated axial and radial diffusivity in Friedreich's ataxia (FRDA) which is characterized by selective neuronal loss of the dentate nuclei and atrophy and decreased FA of the superior cerebellar peduncles (SCPs).Axial and radial diffusivity of the whole-brain WM were evaluated in 14 patients with FRDA and 14 healthy volunteers using DTI at 1.5 T and the tract-based spatial statistics (TBSS) method, part of FSL software.TBSS analysis showed a single area in the central midbrain corresponding to the decussation of the SCPs which exhibited lower FA in patients than in controls. In this area, a significant increase of both axial and radial diffusivity was observed. No clusters of significantly decreased axial diffusivity were observed, while additional clusters of increase of radial diffusivity were present throughout the brain.The selective decrease of FA in SCPs of FRDA patients reflecting chronic WM tract damage is associated with increase of both the axial and radial diffusivity, the latter more pronounced than the former. The ultrastructural and biophysical bases of the increased axial diffusivity in chronically degenerating WM tracts deserve further studies.