Middlebrooks Erik H, Holanda Vanessa M, Tuna Ibrahim S, Deshpande Hrishikesh D, Bredel Markus, Almeida Leonardo, Walker Harrison C, Guthrie Barton L, Foote Kelly D, Okun Michael S
Department of Radiology, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL, 32224, USA.
Department of Neurosurgery, University of Florida, Gainesville, FL, USA.
Neuroradiology. 2018 Mar;60(3):303-309. doi: 10.1007/s00234-017-1972-2. Epub 2018 Jan 6.
Deep brain stimulation is a common treatment for medication-refractory essential tremor. Current coordinate-based targeting methods result in variable outcomes due to variation in thalamic structure and the optimal patient-specific functional location. The purpose of this study was to compare the coordinate-based pre-operative targets to patient-specific thalamic segmentation utilizing a probabilistic tractography methodology.
Using available diffusion MRI of 32 subjects from the Human Connectome Project database, probabilistic tractography was performed. Each thalamic voxel was coded based on one of six predefined cortical targets. The segmentation results were analyzed and compared to a 2-mm spherical target centered at the coordinate-based location of the ventral intermediate thalamic nucleus.
The traditional coordinate-based target had maximal overlap with the junction of the region most connected to primary motor cortex (M1) (36.6 ± 25.7% of voxels on left; 58.1 ± 28.5% on right) and the area connected to the supplementary motor area/premotor cortex (SMA/PMC) (44.9 ± 21.7% of voxels on left; 28.9 ± 22.2% on right). There was a within-subject coefficient of variation from right-to-left of 69.4 and 63.1% in the volume of overlap with the SMA/PMC and M1 regions, respectively.
Thalamic segmentation based on structural connectivity measures is a promising technique that may enhance traditional targeting methods by generating reproducible, patient-specific pre-operative functional targets. Our results highlight the problematic intra- and inter-subject variability of indirect, coordinate-based targets. Future prospective clinical studies will be needed to validate this targeting methodology in essential tremor patients.
脑深部电刺激是药物难治性特发性震颤的常用治疗方法。由于丘脑结构的变异以及患者特异性最佳功能位置的差异，当前基于坐标的靶点定位方法会导致不同的治疗结果。本研究的目的是利用概率性纤维束成像方法，将基于坐标的术前靶点与患者特异性丘脑分割进行比较。
使用来自人类连接体项目数据库的32名受试者的可用扩散磁共振成像进行概率性纤维束成像。每个丘脑体素根据六个预定义皮质靶点之一进行编码。分析分割结果，并与以丘脑腹中间核基于坐标的位置为中心的2毫米球形靶点进行比较。
传统的基于坐标的靶点与最连接初级运动皮层（M1）的区域交界处（左侧体素的36.6±25.7%；右侧58.1±28.5%）以及连接辅助运动区/运动前皮层（SMA/PMC）的区域（左侧体素的44.9±21.7%；右侧28.9±22.2%）有最大重叠。与SMA/PMC和M1区域重叠体积的左右侧受试者内变异系数分别为69.4%和63.1%。
基于结构连接性测量的丘脑分割是一种有前景的技术，通过生成可重复的、患者特异性的术前功能靶点，可能会增强传统靶点定位方法。我们的结果突出了间接基于坐标的靶点在受试者内和受试者间存在问题的变异性。未来需要前瞻性临床研究来验证这种靶点定位方法在特发性震颤患者中的有效性。
