Enhanced co-registration methods to improve intracranial electrode contact localization
Enhanced co-registration methods to improve intracranial electrode contact localization
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DOI：
10.1016/j.nicl.2018.07.026
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发表时间：
2018-01-01
影响因子：
4.2
通讯作者：
Moxon, Karen A.
中科院分区：
文献类型：
--
作者：
Hinds, Walter A.;Misra, Amrit;Moxon, Karen A.
背景资料：当计划定制的脑部手术以识别切除的病理组织并相反地避免功能组织时，电极接触位置是重要的。目前的方法采用训练有素的专家使用神经成像扫描，手动配准和定位接触在2 mm内。然而，现有技术受到每种类型颅内电极所需的专业知识或模态间配准的限制，这会增加误差，降低准确性。患者通常有各种各样的电极条、网格和植入深度;因此，对每种类型的电极应用单独的定位方法既麻烦又耗时，需要不同方法的专业知识。新方法：为了克服这些限制，开发了一种计算方法，通过将植入物磁共振图像（MRI）和植入物计算机断层扫描图像（CT）分别配准到植入前MRI，然后计算一个迭代的最近点变换使用的接触位置提取的信号void作为ground truth.Results：植入MRI是鲁棒的共注册到植入前MRI与基于边界的配准算法。通过提取和利用“信号空白”（来自植入物MRI的金属诱导伪影）作为电极基准，新方法是一种用于所有类型颅内电极的一体化方法，同时消除了模态间共配准误差。测量每个电极质心与大脑表面之间的距离，对于所提出的方法以及使用两个可用软件包SPM 12和FSL 4.1的最新方法。这里提出的方法实现了最小的距离到大脑的表面的所有条和网格型电极，即接触设计直接放在大脑surfaces.Conclusion：我们使用的最大的报告样本量在本地化研究，以验证这种新的方法，用于本地化不同种类的颅内电极，包括网格，条带和深度电极。
Background: Electrode contact locations are important when planning tailored brain surgeries to identify pathological tissue targeted for resection and conversely avoid eloquent tissue. Current methods employ trained experts to use neuroimaging scans that are manually co-registered and localize contacts within similar to 2 mm. Yet, the state of the art is limited by either the expertise needed for each type of intracranial electrode or the intermodality co-registration which increases error, reducing accuracy. Patients often have a variety of strips, grids and depths implanted; therefore, it is cumbersome and time-consuming to apply separate localization methods for each type of electrode, requiring expertise across different approaches.New method: To overcome these limitations, a computational method was developed by separately registering an implant magnetic resonance image (MRI) and implant computed tomography image (CT) to the pre-implant MRI, then calculating an iterative closest point transformation using the contact locations extracted from the signal voids as ground truth.Results: The implant MRI is robustly co-registered to the pre-implant MRI with a boundary-based registration algorithm. By extracting and utilizing 'signal voids' (the metal induced artifacts from the implant MRI) as electrode fiducials, the novel method is an all-in-one approach for all types of intracranial electrodes while eliminating inter-modality co-registration errors.Comparison with existing methods: The distance between each electrode centroid and the brain's surface was measured, for the proposed method as well as the state of the art method using two available software packages, SPM 12 and FSL 4.1. The method presented here achieves the smallest distances to the brain's surface for all strip and grid type electrodes, i.e. contacts designed to rest directly on the brain surface.Conclusion: We use one of the largest reported sample sizes in localization studies to validate this novel method for localizing different kinds of intracranial electrodes including grids, strips and depth electrodes.