Department of Biostatistics, and Biomedical ResearchImaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC27599, USA.
IEEE Trans Med Imaging. 2010 Apr;29(4):1039-49. doi: 10.1109/TMI.2010.2040625. Epub 2010 Mar 22.
Diffusion tensor imaging (DTI) provides important information on the structure of white matter fiber bundles as well as detailed tissue properties along these fiber bundles in vivo. This paper presents a functional regression framework, called FRATS, for the analysis of multiple diffusion properties along fiber bundle as functions in an infinite dimensional space and their association with a set of covariates of interest, such as age, diagnostic status and gender, in real applications. The functional regression framework consists of four integrated components: the local polynomial kernel method for smoothing multiple diffusion properties along individual fiber bundles, a functional linear model for characterizing the association between fiber bundle diffusion properties and a set of covariates, a global test statistic for testing hypotheses of interest, and a resampling method for approximating the p-value of the global test statistic. The proposed methodology is applied to characterizing the development of five diffusion properties including fractional anisotropy, mean diffusivity, and the three eigenvalues of diffusion tensor along the splenium of the corpus callosum tract and the right internal capsule tract in a clinical study of neurodevelopment. Significant age and gestational age effects on the five diffusion properties were found in both tracts. The resulting analysis pipeline can be used for understanding normal brain development, the neural bases of neuropsychiatric disorders, and the joint effects of environmental and genetic factors on white matter fiber bundles.
弥散张量成像（DTI）提供了关于白质纤维束结构的重要信息，以及这些纤维束内的详细组织特性。本文提出了一种功能回归框架，称为 FRATS，用于分析沿纤维束的多个扩散特性作为无限维空间中的函数，以及它们与一组感兴趣的协变量（如年龄、诊断状态和性别）的关联，在实际应用中。功能回归框架由四个集成组件组成：局部多项式核方法用于平滑沿单个纤维束的多个扩散特性，功能线性模型用于描述纤维束扩散特性与一组协变量之间的关联，全局检验统计量用于检验感兴趣的假设，以及重采样方法用于逼近全局检验统计量的 p 值。该方法学应用于在一项神经发育的临床研究中描述五个扩散特性（包括各向异性分数、平均扩散率以及弥散张量的三个特征值）沿胼胝体压部束和右侧内囊束的发育情况。在这两个束中均发现了年龄和胎龄对五个扩散特性的显著影响。所得的分析流程可用于理解正常大脑发育、神经精神障碍的神经基础以及环境和遗传因素对白质纤维束的联合影响。
