Department of Neurosurgery David Geffen School of Medicine, UCLA, Los Angeles, CA, USA.
Department of Neurosurgery David Geffen School of Medicine, UCLA, Los Angeles, CA, USA.
Neuroimage Clin. 2017 Dec 12;17:1019-1027. doi: 10.1016/j.nicl.2017.12.018. eCollection 2018.
Magnetic Resonance-guided Focused UltraSound (MRgFUS) offers an incisionless approach to treat essential tremor (ET). Due to lack of evident internal anatomy on traditional structural imaging, indirect targeting must still be used to localize the lesion. Here, we investigate the potential predictive value of probabilistic tractography guided thalamic targeting by defining how tractography-defined targets, lesion size and location, and clinical outcomes interrelate. MR imaging and clinical outcomes from 12 ET patients that underwent MRgFUS thalamotomy in a pilot study at the University of Virginia were evaluated in this analysis. FSL was used to evaluate each patient's voxel-wise thalamic connectivity with FreeSurfer generated pre- and post-central gyrus targets, to generate thalamic target maps. Using Receiver Operating Characteristic curves, the overlap between these thalamic target maps and the MRgFUS lesion was systematically evaluated relative to clinical outcome. To further define the connectivity characteristics of effective MRgFUS thalamotomy lesions, we evaluated whole brain probabilistic tractography of lesions (using post-treatment imaging to define the lesion pre-treatment diffusion tensor MRI). The structural connectivity difference was explored between subjects with the best clinical outcome relative to all others. Ten of twelve patients presented high percentage of overlapping between connectivity-based thalamic segmentation maps and lesion area. The improvement of clinical score was predicted (AUC: 0.80) using the volume of intersection between the thalamic target (precentral gyrus) map and MRgFUS induced lesion as feature. The main structural differences between those with different magnitudes of response were observed in connectivity to the pre- and post-central gyri and brainstem/cerebellum. MRgFUS thalamotomy lesions characterized by strong structural connectivity to precentral gyrus demonstrated better responses in a cohort of patients treated with MRgFUS for ET. The intersection between lesion and thalamic-connectivity maps to motor - sensory targets proved to be effective in predicting the response to the therapy. These imaging techniques can be used to increase the efficacy and consistency of outcomes with MRgFUS and potentially shorten treatment times by identifying optimal targets in advance of treatment.
磁共振引导聚焦超声（MRgFUS）为治疗原发性震颤（ET）提供了一种非侵入性的方法。由于传统结构成像上缺乏明显的内部解剖结构，仍必须使用间接靶向来定位病变。在这里，我们通过定义轨迹定义的靶点、病变大小和位置以及临床结果之间的关系，研究了基于概率轨迹引导丘脑靶向的潜在预测价值。我们对弗吉尼亚大学进行的一项先导研究中接受 MRgFUS 丘脑切开术的 12 名 ET 患者的 MR 成像和临床结果进行了分析。使用 FSL 评估了每位患者的丘脑与 FreeSurfer 生成的中央前回和中央后回靶点之间的每体素连接，以生成丘脑靶点图。使用接收器操作特征曲线，系统地评估了这些丘脑靶点图与 MRgFUS 病变之间的重叠与临床结果的关系。为了进一步定义有效的 MRgFUS 丘脑切开术病变的连接特征，我们对病变的全脑概率轨迹进行了评估（使用治疗后的成像来定义治疗前的弥散张量 MRI 中的病变）。我们在所有其他人中，探索了具有最佳临床效果的受试者之间的结构连接差异。12 名患者中有 10 名患者表现出基于连接的丘脑分割图与病变区域之间具有较高的重叠百分比。使用丘脑目标（中央前回）图与 MRgFUS 诱导的病变之间的交集体积作为特征，可以预测临床评分的改善（AUC：0.80）。那些具有不同反应程度的人之间的主要结构差异在与中央前回和后回以及脑干/小脑的连接中观察到。在接受 MRgFUS 治疗 ET 的患者中，具有与中央前回强烈结构连接的 MRgFUS 丘脑切开术病变表现出更好的反应。病变与运动-感觉靶点的连接性之间的交点证明可以有效地预测治疗反应。这些成像技术可以用于提高 MRgFUS 的疗效和一致性，并通过在治疗前确定最佳靶点来潜在缩短治疗时间。
