ESM-CT：一种在 CT 图像中对 DBS 电极进行精确定位的方法。
ESM-CT: a precise method for localization of DBS electrodes in CT images.
机构信息
Mallinckrodt Institute of Radiology, Department of Radiology, Washington University School of Medicine, (CB 8225), 660 S. Euclid Avenue, St. Louis, MO, 63110, USA.
Mallinckrodt Institute of Radiology, Department of Radiology, Washington University School of Medicine, (CB 8225), 660 S. Euclid Avenue, St. Louis, MO, 63110, USA; Department of Neurology, Washington University School of Medicine, (CB 8111), 660 S. Euclid Avenue, St. Louis, MO, 63110, USA.
出版信息
J Neurosci Methods. 2018 Oct 1;308:366-376. doi: 10.1016/j.jneumeth.2018.09.009. Epub 2018 Sep 7.
BACKGROUND
Deep brain stimulation (DBS) of the subthalamic nucleus produces variable effects in Parkinson disease. Variation may result from different electrode positions relative to target. Thus, precise electrode localization is crucial when investigating DBS effects.
NEW METHOD
We developed a semi-automated method, Electrode Shaft Modeling in CT images (ESM-CT) to reconstruct DBS lead trajectories and contact locations. We evaluated methodological sensitivity to operator-dependent steps, robustness to image resampling, and test-retest replicability. ESM-CT was applied in 56 patients to study electrode position change (and relation to time between scans, postoperative subdural air volume, and head tilt during acquisition) between images acquired immediately post-implantation (DBS-CT) and months later (DEL-CT).
RESULTS
Electrode tip localization was robust to image resampling and replicable to within ∼ 0.2 mm on test-retest comparisons. Systematic electrode displacement occurred rostral-ventral-lateral between DBS-CT and DEL-CT scans. Head angle was a major explanatory factor (p < 0.001,Pearson's r = 0.46, both sides) and volume of subdural air weakly predicted electrode displacement (p = 0.02,r = 0.29:p = 0.1,r = 0.25 for left:right). Modeled shaft curvature was slightly greater in DEL-CT. Magnitude of displacement and degree of curvature were independent of elapsed time between scans.
COMPARISON WITH EXISTING METHODS
Comparison of ESM-CT against two existing methods revealed systematic differences in one coordinate (1 ± 0.3 mm,p < 0.001) for one method and in three coordinates for another method (x:0.1 ± 0.1 mm, y:0.4 ± 0.2 mm, z:0.4 ± 0.2 mm, p < 10). Within-method coordinate variability across participants is similar.
CONCLUSION
We describe a robust and precise method for CT DBS contact localization. Application revealed that acquisition head angle significantly impacts electrode position. DBS localization schemes should account for head angle.
背景
丘脑底核深部脑刺激（DBS）在帕金森病中产生不同的效果。这种差异可能是由于电极相对于靶点的位置不同所致。因此，在研究 DBS 效果时，精确的电极定位至关重要。
方法
我们开发了一种半自动方法，即 CT 图像中的电极轴建模（ESM-CT），用于重建 DBS 导联轨迹和接触位置。我们评估了方法对操作人员依赖性步骤的敏感性、对图像重采样的稳健性以及测试-重测可重复性。ESM-CT 应用于 56 例患者，以研究植入后即刻（DBS-CT）和数月后（DEL-CT）采集的图像之间电极位置的变化（以及与扫描之间的时间、术后硬膜下空气量和采集时头部倾斜的关系）。
结果
电极尖端定位对图像重采样具有稳健性，并且在测试-重测比较中可重复性在 0.2mm 以内。DBS-CT 和 DEL-CT 扫描之间，电极发生了向头侧-腹侧-外侧的系统位移。头部角度是一个主要的解释因素（p<0.001，Pearson r=0.46，双侧），硬膜下空气量也可微弱预测电极位移（p=0.02，r=0.29：p=0.1，r=0.25：左侧/右侧）。DEL-CT 中模型化轴的曲率稍大。位移的大小和曲率的程度与扫描之间的时间无关。
与现有方法的比较
将 ESM-CT 与两种现有方法进行比较，发现一种方法在一个坐标上存在系统差异（1±0.3mm，p<0.001），另一种方法在三个坐标上存在差异（x：0.1±0.1mm，y：0.4±0.2mm，z：0.4±0.2mm，p<10）。参与者内的方法坐标变异性相似。
结论
我们描述了一种用于 CT DBS 接触定位的稳健且精确的方法。应用结果表明，采集时的头部角度显著影响电极位置。DBS 定位方案应考虑头部角度。
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