Compensating for intraoperative soft-tissue deformations using incomplete surface data and finite elements
Compensating for intraoperative soft-tissue deformations using incomplete surface data and finite elements
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DOI：
10.1109/tmi.2005.855434
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发表时间：
2005-11-01
影响因子：
10.6
通讯作者：
Chapman, WC
中科院分区：
文献类型：
--
作者：
Cash, DM;Miga, MI;Chapman, WC
图像引导肝脏手术需要能够识别和补偿器官中的软组织变形。预变形状态表示为器官的完整三维表面，而术中数据是从暴露的肝脏表面获取的范围扫描点云。第一步是严格对齐术中和术前数据的坐标系。大多数传统的刚性配准方法都会最小化整个数据集的误差度量。在本文中，报告了一种新的变形识别刚性配准（DIRR），它使用修改后的最近点距离成本函数来识别和对齐数据的最小变形区域。一旦建立了刚性对准，就可以使用线性弹性有限元模型 (FEM) 来计算变形，并使用增量框架来解决几何非线性问题。增量公式的边界条件是从术中获取的暴露肝脏表面的范围扫描表面生成的。提出了一系列模型实验来分别评估 DIRR 和组合的 DIRR/FEM 方法的保真度。 DIRR 方法在真实手术暴露条件下识别出 90% 病例的变形区域。对于 DIRR/FEM 算法，在模型实验中，地下目标误差被正确定位在 4 mm 以内。
Image-guided liver surgery requires the ability to identify and compensate for soft tissue deformation in the organ. The predeformed state is represented as a complete three-dimensional surface of the organ, while the intraoperative data is a range scan point cloud acquired from the exposed liver surface. The first step is to rigidly align the coordinate systems of the intraoperative and preoperative data. Most traditional rigid registration methods minimize an error metric over the entire data set. In this paper, a new deformation-identifying rigid registration (DIRR) is reported that identifies and aligns minimally deformed regions of the data using a modified closest point distance cost function. Once a rigid alignment has been established, deformation is accounted for using a linearly elastic finite element model (FEM) and implemented using an incremental framework to resolve geometric nonlinearities. Boundary conditions for the incremental formulation are generated from intraoperatively acquired range scan surfaces of the exposed liver surface. A series of phantom experiments is presented to assess the fidelity of the DIRR and the combined DIRR/FEM approaches separately. The DIRR approach identified deforming regions in 90% of cases under conditions of realistic surgical exposure. With respect to the DIRR/FEM algorithm, subsurface target errors were correctly located to within 4 mm in phantom experiments.