基于全变差空间正则化的纤维方向分布估计  

Total Variation Based Spatial Brain Fiber Orientation Estimation

作　　者：李斐[1] 冯远静[1] 吴烨[1] 

机构地区：[1]浙江工业大学信息工程学院,杭州310023

出　　处：《系统科学与数学》2017年第1期23-32,共10页Journal of Systems Science and Mathematical Sciences

基　　金：国家自然科学基金(61379020;61075062);浙江省自然科学基金(LY13F0300067);温州医科大学重中之重学科基金(LKFJ014)资助课题

摘　　要：提高白质纤维交叉重构能力是有效提高纤维跟踪技术的前提之一,目前大多纤维重构方法都是基于白质体素的独立重构,没有考虑到纤维的连续性特征,这就促使文章从全局范围考虑提高白质纤维重构能力.文章提出了一种基于全变差空间正则化的纤维方向分布估计方法,该方法首先利用字典基分布的球面反卷积策略拟合多壳采样信号,为了能够适用于单壳和多壳采样方案,文章重新定义了广义的纤维响应函数;进而在q空间中定义基函数系数的全变差正则化约束,旨在减少不必要的方向信息,降低因噪声引起的方向偏差,以获得纤维方向的空间局部一致性.实验分别在模拟数据和实际数据下进行,分别采用单壳和多壳数据验证了文章所提方法能够以更高效的性能实现纤维方向估计,相对于其他算法显著提高了纤维的连续性.It is an important prerequisite of development of tractography to improve the accuracy of crossing fiber reconstruction. Most of the existing reconstructing methods are voxel-wise, which are sub-optimal for the disregard of the fiber consis- tency. Thus, in this work we propose a global fiber estimation method based on local sparsity and spatial total variation regularization to improve the accuracy of fiber ori- entation distribution. Firstly, spherical deconvolution based on a dictionary basis is built for the multi-shell signal fitting, in which the response function is re-estimated with different sensitive coefficients. Then a total variation in the q-space is forced on the basis function coefficients to guarantee the spatial consistency of brain fiber,which eliminates the spurious directions caused by noise. The results of experiments on simulated and in vivo data demonstrate the efl：iciency of the proposed methods in fiber orientation estimation when single-shell and multi-shell data involved, and compared with other methods, the present methods shows a prominent superiority in fiber consistency.

关 键 词：白质纤维重构 多壳采样 球面反卷积 全变差正则化 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]