Zhang Yu, Wu I-Wei, Buckley Shannon, Coffey Christopher S, Foster Eric, Mendick Susan, Seibyl John, Schuff Norbert
Center for Imaging of Neurodegenerative Diseases, San Francisco VA Medical Center, San Francisco, CA, USA.
Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA.
Mov Disord. 2015 Aug;30(9):1229-36. doi: 10.1002/mds.26251. Epub 2015 Apr 29.
Parkinson's disease (PD) is histopathologically characterized by the loss of dopamine neurons in the substantia nigra pars compacta. The depletion of these neurons is thought to reduce the dopaminergic function of the nigrostriatal pathway, as well as the neural fibers that link the substantia nigra to the striatum (putamen and caudate), causing a dysregulation in striatal activity that ultimately leads to lack of movement control. Based on diffusion tensor imaging, visualizing this pathway and measuring alterations of the fiber integrity remain challenging. The objectives were to 1) develop a diffusion tensor tractography protocol for reliably tracking the nigrostriatal fibers on multicenter data; 2) test whether the integrities measured by diffusion tensor imaging of the nigrostriatal fibers are abnormal in PD; and 3) test whether abnormal integrities of the nigrostriatal fibers in PD patients are associated with the severity of motor disability and putaminal dopamine binding ratios.
Diffusion tensor tractography was performed on 50 drug-naïve PD patients and 27 healthy control subjects from the international multicenter Parkinson's Progression Marker Initiative.
Tractography consistently detected the nigrostriatal fibers, yielding reliable diffusion measures. Fractional anisotropy, along with radial and axial diffusivity of the nigrostriatal tract, showed systematic abnormalities in patients. In addition, variations in fractional anisotropy and radial diffusivity of the nigrostriatal tract were associated with the degree of motor deficits in PD patients.
Taken together, the findings imply that the diffusion tensor imaging characteristic of the nigrostriatal tract is potentially an index for detecting and staging of early PD.
帕金森病（PD）在组织病理学上的特征是黑质致密部多巴胺能神经元缺失。这些神经元的耗竭被认为会降低黑质纹状体通路的多巴胺能功能，以及连接黑质与纹状体（壳核和尾状核）的神经纤维，导致纹状体活动失调，最终导致运动控制缺失。基于扩散张量成像，可视化这条通路并测量纤维完整性的改变仍然具有挑战性。目标是：1）制定一种扩散张量纤维束成像方案，以可靠地追踪多中心数据上的黑质纹状体纤维；2）测试通过扩散张量成像测量的黑质纹状体纤维完整性在PD中是否异常；3）测试PD患者黑质纹状体纤维的异常完整性是否与运动残疾的严重程度和壳核多巴胺结合率相关。
对来自国际多中心帕金森病进展标志物倡议的50例未接受过药物治疗的PD患者和27名健康对照者进行扩散张量纤维束成像。
纤维束成像始终能检测到黑质纹状体纤维，产生可靠的扩散测量值。患者的各向异性分数以及黑质纹状体束的径向和轴向扩散率显示出系统性异常。此外，黑质纹状体束的各向异性分数和径向扩散率的变化与PD患者的运动缺陷程度相关。
综上所述，这些发现表明黑质纹状体束的扩散张量成像特征可能是早期PD检测和分期的一个指标。
