Hosey Tim, Williams Guy, Ansorge Richard
The Cavendish Laboratory, University of Cambridge, UK.
Magn Reson Med. 2005 Dec;54(6):1480-9. doi: 10.1002/mrm.20723.
A method is presented that is capable of determining more than one fiber orientation within a single voxel in high angular resolution diffusion imaging (HARDI) data sets. This method is an extension of the Markov chain method recently introduced to diffusion tensor imaging (DTI) analysis, allowing the probability density function of up to 2 intra-voxel fiber orientations to be inferred. The multiple fiber architecture within a voxel is then assessed by calculating the relative probabilities of a 1 and 2 fiber model. It is demonstrated that for realistic signal to noise ratios, it is possible to accurately characterize the directions of 2 intersecting fibers using a 2 fiber model. The shortcomings of under-fitting a 2 fiber model, or over-fitting a 1 fiber model, are explored. This new algorithm enhances the tools available for fiber tracking.
本文提出了一种方法，该方法能够在高角分辨率扩散成像（HARDI）数据集中确定单个体素内的多个纤维方向。此方法是最近引入扩散张量成像（DTI）分析的马尔可夫链方法的扩展，可推断多达2个体素内纤维方向的概率密度函数。然后通过计算单纤维模型和双纤维模型的相对概率来评估体素内的多纤维结构。结果表明，对于实际的信噪比，使用双纤维模型可以准确地表征两条相交纤维的方向。本文还探讨了双纤维模型拟合不足或单纤维模型过度拟合的缺点。这种新算法增强了纤维追踪可用的工具。
