Prasad Shweta, Rajan Archith, Bharath Rose Dawn, Saini Jitender, Pal Pramod Kumar
Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health & Neurosciences, Hosur Road, Bangalore, Karnataka, 560029, India.
Department of Neurology, National Institute of Mental Health & Neurosciences (NIMHANS), Hosur Road, Bengaluru, Karnataka, 560029, India.
Neuroradiology. 2025 Apr;67(4):909-920. doi: 10.1007/s00234-025-03542-z. Epub 2025 Jan 20.
The dentato-rubro-thalamo-cortical tract (DRTC) is considered to play a crucial role across tremor disorders including tremor dominant Parkinson's disease (TDPD) and essential tremor plus (ETP). This study aims to comprehensively evaluate microstructural integrity of the DRTC using single-compartment, i.e., DTI, and multi-compartment, i.e., neurite orientation dispersion and distribution imaging (NODDI), and free water (FW) based analysis.
DTI, NODDI and FW based metrics were estimated for 25 TDPD, 25 ETP (Essential tremor with rest tremor) and 22 healthy controls (HC). TBSS was carried out followed by voxelwise statistics on respective metric skeletons with TFCE correction and custom FA skeleton masks for left and right DRTC tracts. Masks generated from significant clusters, and whole tract masks were utilised in quantitative analysis. ROI based subject space analysis was also carried out for whole tract and TBSS cluster values. Quantitative analysis was carried out using MANCOVA with age and gender as covariates. Clinical features between TDPD and ETP were compared using t-test.
There was no difference in the Fahn-Tolosa-Marin tremor rating scale score. Compared to HC, TDPD showed lower neurite density index, higher axial diffusivity (AD), mean diffusivity (MD), FW corrected MD in the thalamo-cortical section of the left DRTC. No statistically significant differences were observed between ETP and HC or TDPD and ETP.
TDPD demonstrated asymmetric reduction in neurite density and increased MD, fwMD and AD in the thalamo-cortical section of DRTC. The absence of differences between ETP and TDPD may suggest the possibility of similarities in tremor pathogenesis.
齿状核-红核-丘脑-皮质束（DRTC）被认为在包括震颤为主型帕金森病（TDPD）和特发性震颤伴静止性震颤（ETP）在内的各种震颤疾病中起关键作用。本研究旨在使用单室分析（即扩散张量成像，DTI）、多室分析（即神经突方向离散度和密度成像，NODDI）以及基于自由水（FW）的分析方法，全面评估DRTC的微观结构完整性。
对25例TDPD患者、25例ETP患者（特发性震颤伴静止性震颤）和22名健康对照者（HC）进行DTI、NODDI和基于FW的指标评估。采用基于体素的空间统计分析（TBSS），随后对各指标骨架进行体素水平统计，并进行基于TFCE校正以及针对左右DRTC束的自定义各向异性分数（FA）骨架掩码分析。由显著簇生成的掩码以及全束掩码用于定量分析。还对全束和TBSS簇值进行了基于感兴趣区域（ROI）的个体空间分析。以年龄和性别作为协变量，采用多变量协方差分析（MANCOVA）进行定量分析。使用t检验比较TDPD和ETP之间的临床特征。
Fahn-Tolosa-Marin震颤评分量表得分无差异。与HC相比，TDPD患者左侧DRTC丘脑-皮质段的神经突密度指数较低，轴向扩散率（AD）、平均扩散率（MD）、自由水校正平均扩散率（fwMD）较高。ETP与HC之间或TDPD与ETP之间未观察到统计学上的显著差异。
TDPD患者DRTC丘脑-皮质段神经突密度不对称降低，MD、fwMD和AD增加。ETP与TDPD之间无差异可能提示震颤发病机制存在相似性。
