中文摘要：

传统的快速行进算法重建结果多假性阳支，不能很好地反映纤维走向，为此提出一种新颖的拓扑保持快速行进算法．首先将曲率引入速度函数，并将弯曲能量考虑到全局能量范围内，以更好地控制曲面演化过程，更清晰地描述纤维走向．该算法可应用到脑肿瘤病理诊断和治疗中，通过体绘制技术将同一病人的扩散张量成像（DTI）和磁共振成像（MRI）融合，以显示脑白质纤维束因占位效应或者病变所导致的位置异常，提高DTI在临床应用方面的效用．采用文中算法的重建结果具有较好的拓扑结构，并且对噪声有较好的鲁棒性．

英文摘要：

One problem of traditional fast marching method （FM） for DTI is to trace the wrong pathways, thereby reflect the incorrect fiber tendency in particular regions. To solve this problem, topology persevered model is proposed in this paper to help the pathways revolve in a reasonable way. This optimized algorithm refines the evolution process by introducing curvature into the speed function. The reconstruction results using our method show that topology structures are well kept and fiber directions are clearer. Additionally, it is robust to noise. The possible application is medical diagnosis and brain tumor treatment. By combining magnetic resonance imaging （MRI） and diffusion tensor imaging （DTI） information of the same patient in a single image, the oppression and pathological changes of tumors is revealed with abnormal position of the fiber. This application will benefit the clinic and medical research.