This study tested an improved fiber tracking algorithm, which was based on fiber assignment using a continuous tracking algorithm and a two-tensor model. Different models and tracking decisions were used by judging th...This study tested an improved fiber tracking algorithm, which was based on fiber assignment using a continuous tracking algorithm and a two-tensor model. Different models and tracking decisions were used by judging the type of estimation of each voxel. Thismethod should solve the cross-track problem. This study included eight healthy subjects, two axonal injury patients and seven demyelinating disease patients. This new algorithm clearly exhibited a difference in nerve fiber direction between axonal injury and demyelinating disease patients and healthy control subjects. Compared with fiber assignment with a continuous tracking algorithm, our novel method can track more and longer nerve fibers, and also can solve the fiber crossing problem.展开更多
依据最大间距判别准则(Maximum margin criterion,MMC)的基本原理,并结合模糊技术和张量理论,提出一种矩阵模式的模糊最大间距判别准则(Matrix model fuzzy maximum margin criterion,MFMMC),并在此基础上形成具有模糊聚类功能的双向二...依据最大间距判别准则(Maximum margin criterion,MMC)的基本原理,并结合模糊技术和张量理论,提出一种矩阵模式的模糊最大间距判别准则(Matrix model fuzzy maximum margin criterion,MFMMC),并在此基础上形成具有模糊聚类功能的双向二维无监督特征提取方法(Two-directional two-dimensional unsupervised feature extraction method with fuzzy clustering ability,(2D)2UFFCA).该方法不但能直接实现矩阵模式数据的模糊聚类,而且还可以对矩阵模式数据进行双向二维特征提取,实现特征降维.同时我们还从几何的直观含义出发,合理地设定矩阵模式的模糊最大间距判别准则中的调节参数γ,并从理论上证明其合理性.为了提高特征提取的效率,还提出一种能有效计算矩阵模式数据的投影变换矩阵的方法.实验结果表明该方法具有上述优势.展开更多
We propose a method of reliable tracking orientation and flexible step size fiber tracking. A new directional strategy was defined to select one optimal tracking orientation from each directional set, which was based ...We propose a method of reliable tracking orientation and flexible step size fiber tracking. A new directional strategy was defined to select one optimal tracking orientation from each directional set, which was based on the single-tensor model and the two-tensor model. The directional set of planar voxels contained three tracking directions： two from the two-tensor model and one from the single- tensor model. The directional set of linear voxels contained only one principal vector. In addition, a flexible step size, rather than fixable step sizes, was implemented to improve the accuracy of fiber tracking. We used two sets of human data to assess the performance of our method; one was from a healthy volunteer and the other from a patient with low-grade glioma. Results verified that our method was superior to the single-tensor Fiber Assignment by Continuous Tracking and the two-tensor eXtended Streamline Tractography for showing detailed images of fiber bundles.展开更多
基金supported by Xiamen Technology Projects Grand (The study of chronic cerebrovascular insufficiently in Magnetic Resonance Imaging), No.3502Z20084028
文摘This study tested an improved fiber tracking algorithm, which was based on fiber assignment using a continuous tracking algorithm and a two-tensor model. Different models and tracking decisions were used by judging the type of estimation of each voxel. Thismethod should solve the cross-track problem. This study included eight healthy subjects, two axonal injury patients and seven demyelinating disease patients. This new algorithm clearly exhibited a difference in nerve fiber direction between axonal injury and demyelinating disease patients and healthy control subjects. Compared with fiber assignment with a continuous tracking algorithm, our novel method can track more and longer nerve fibers, and also can solve the fiber crossing problem.
基金Supported by the Youth Foundation of Jiangxi Provincial Education Department(GJJ13376)the Foundation of the Jiangxi University of Science and Technology(jxxj12073)
基金supported by the Science and Technology Commission of the Shanghai Municipality of China,No.10dz2211800,No.10XD1421400the National High Technology Research and Development Program,No.2009AA02Z415the Innovation Program of Shanghai Municipal Education Commission,No.11yz292
文摘We propose a method of reliable tracking orientation and flexible step size fiber tracking. A new directional strategy was defined to select one optimal tracking orientation from each directional set, which was based on the single-tensor model and the two-tensor model. The directional set of planar voxels contained three tracking directions： two from the two-tensor model and one from the single- tensor model. The directional set of linear voxels contained only one principal vector. In addition, a flexible step size, rather than fixable step sizes, was implemented to improve the accuracy of fiber tracking. We used two sets of human data to assess the performance of our method; one was from a healthy volunteer and the other from a patient with low-grade glioma. Results verified that our method was superior to the single-tensor Fiber Assignment by Continuous Tracking and the two-tensor eXtended Streamline Tractography for showing detailed images of fiber bundles.
