中文摘要：

脑组织牵拉变形严重影响神经导航系统（IGNS）术中导航的精确性及可靠性。建立脑组织线弹性生物力学模型，利用扩展有限元方法（XFEM）矫正发生牵拉变形的生物力学模型。借助植入脑组织体模内的不锈钢标记物牵拉前后图像中位移定量分析XFEM矫正脑组织牵拉变形的有效性。试验中不同尺寸网格的XFEM系统框架预测误差在0．3～0．5mm之间，平均为0．4mm；矫正精度在83．1％～87．5％之间，平均85．9％。结果表明，该系统框架能够有效矫正脑组织牵拉变形。

英文摘要：

Brain retraction severely decreases the accuracy and reliability of Image Guided Navigation Systems （IGNS）. In this paper, we proposed a linear elastic framework in which extended finite element method （XFEM） was used for the correction of the brain retraction. We performed a quantitative assessment of brain retraction framework by the displacement of implanted metal makers in one brain phantom. The average correction error of our XFEM framework varied between 0.3mm and 0.5mm （mean 0.4mm）. And the average correction accuracy varied between 83.1% and 87.5% （mean 85.9% ）. The results of the experiments indicated this framework had a great potential to correct brain retraction.