深部脑刺激手术电极三维可视化定位

	深部脑刺激手术电极三维可视化定位
其他题名	Three-dimensional Visualization of Deep Brain StimulationElectrodes Localization
	张芷齐
学位类型	硕士
导师	唐玉国
	2015-10
学位授予单位	中国科学院大学
学位专业	光学工程
关键词	核磁共振影像电子计算机断层扫描影像神经核团刺激电极重建三维可视化
摘要	深部脑刺激（Deep Brain Stimulation，DBS）手术是许多重症神经、精神系统疾病的唯一有效治疗手段，而刺激电极植入的准确性是决定手术成功与否的关键因素。深部脑刺激手术电极植入靶点核团如丘脑底核，体积较小，给刺激电极精确植入带来比较大的困难。目前，临床上通常采用核磁共振影像（Magnetic Resonance Imaging，MRI）或者计算机断层扫描影像（Computed Tomography，CT）来辅助手术电极电位。靶点核团仅能在高分辨率核磁共振影像清晰显示，而术中、术后电极位置确认受金属材质电极影响，仅可采用低分辨率核磁共振设备和计算机断层扫描设备扫描，同时电极伪迹较大亦会给术中、术后电极定位带来很大的困难。因此，以术中、术后影像为基础，实现深部脑刺激手术清晰、直观、准确的电极定位对于临床手术治疗效果的提高具有十分重要的意义。本文以术中、术后核磁共振影像影像以及术后计算机断层扫描影像为基础，实现了深部脑刺激手术空间结构三维可视化算法的设计，为医生提供具有真实感的立体图像，便于刺激电极的位置确认。同时弥补了目前临床二维医学影像无法精确显示植入电极与靶点核团三维空间位置关系的缺陷，在保证精度和速度的前提下，可以满足临床深部脑刺激手术电极定位的需求。主要内容包括以下三个方面： 1. 针对术中、术后影像分辨率低，无法定位核团位置的难题，利用术前高分辨核磁共振扫描影像，将术中、术后影像分别与术前影像配准，进而将术中、术后影像空间标准化到标准立体定向空间，提高标准化算法精度。针对术中电极定位精度以及速度上的要求，采用三步线性算法实现术中核磁共振影像的空间标准化。针对术后影像电极伪迹大，脑组织部分形变的问题，采用DARTEL (Diffeomorphic Anatomical Registration Through Exponentiated Lie Algebra) 非线性算法将术后核磁共振影像标准化到标准立体空间。针对术后CT 影像，利用边缘检测算法与术前核磁共振影像配准，再采用DARTEL 算法空间标准化。结果显示线性算法的匹配误差为1.29 mm，DARTEL 算法的匹配误差为0.96 mm，小于一个像素点。 2. 采用阈值法利用标准化的轴位术中、术后MRI 或者术后CT 自动重建电极植入路径，采用互相关算法自动搜索电极触点，最后利用冠状影像检测、调整电极路径及触点位置，重建结果与临床影像表现一致。 3. 利用现有脑图谱数据，分割丘脑底核、苍白球内侧核等深部脑刺激靶点核团及附近主要神经核团，通过面绘制二值图像重建及伪彩色处理，实现脑组织神经核团的三维可视化，同时融合电极三维影像，完成深部脑刺激手术三维空间结构可视化。采用同样算法实现不同脑图谱相关核团三维可视化，对比刺激电极位置，并由医生判别，结果准确，方便医生多角度确认术中、术后电极位置。本文建立与深部脑刺激相关神经核团空间结构模型，为深部脑刺激神经外科手术功能区定位、最优靶点选择提供指导，为深部脑刺激调控参数优化提供依据，将提高深部脑刺激电极植入精度、改善临床治疗效果、减少副作用和节省电池使用寿命。
其他摘要	Deep brain stimulation (DBS) is the only effective approach for many neural and psychiatric diseases. The accurate implantation of the deep brain stimulation electrodes is the key to the success of the surgery, which has been made harder for the tiny anatomic structure of DBS target nuclei such as subthalamic nucleus. Multimodal medical images like magnetic resonance imaging (MRI) and computed tomography have already been used to assist electrodes localization clinically. While the target nuclei can be easily identified by the high resolution MRI, low resolution MRI or CT scanning are usually applied for intra-operative or post-operative electrodes localization due to the metal property of the electrodes. Therefore, it is essential to develop an accurate electrode localization method based on clinical images for the improvement of the treatment effects. This paper proposed a 3D visualization method based on intra-operative MRI and post-operative MRI/CT for the localization of electrodes in DBS surgery. Being accurate and fast, the proposed technique is expected to provide a vivid stereo image for the neurosurgeon, which could not be realized by the traditional imaging slices. The main contents were as follows. First, the intra-operative and post-operative images were normalized into the standard stereotactic space after co-registration with the high resolution pre-operative MRI, to improve the qualities of low resolution intra- and post-operative images. The intra-operative MRI was normalized by using a 3-step linear algorithm for the fast and precise intra-operative electrodes localization, while the post-operative MRI was normalized into the standard space by the non-linear DARTEL algorithm due to the more significant artifacts and brain tissue deformation caused by the leads. The post-operative CT was also normalized by the DARTEL algorithm after co-registration with the pre-operative MRI based on the edge detecting algorithm. The results showed that the matching error of the linear algorithm was 1.29 mm and 0.96 mm respectively, and the latter one was less than a pixel. Second, the lead trajectories were reconstructed automatically with a specially designed mask based on the normalized axial intra-operative MRI and post-operative MRI/CT. Then the electrode contacts were searched along the lead trajectories by the cross-correlation algorithm. The coronary images were used to revise the reconstructed lead trajectories and contacts. The results were consistent with the clinical operative images. Third, the DBS target nuclei such as subthalamic nuclei and globus pallidus and other nuclei nearby were segmented based on the atlas data, and then was visualized by the binary surface rendering reconstruction algorithm and pseudo-color processing technology in three dimensions, fusing the three-dimensional electrodes model at the same time. The results showed that the location of every electrode was consistent in three different visualization images based on different atlases, and consistent with the clinical treatment by the surgeons. Additionally the 3D visualization could help surgeons check the intra- and post-operative electrode location from different angles.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/49334
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	张芷齐. 深部脑刺激手术电极三维可视化定位[D]. 中国科学院大学,2015.

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