Department of Biomedical Engineering, Yale University, New Haven, CT, USA.
Neuroimage. 2012 Sep;62(3):1510-9. doi: 10.1016/j.neuroimage.2012.05.073. Epub 2012 Jun 1.
Resting-state fMRI (rs-fMRI) holds promise as a clinical tool to characterize and monitor the phenotype of different neurological and psychiatric disorders. The most common analysis approach requires the definition of one or more regions-of-interest (ROIs). However this need for a priori ROI information makes rs-fMRI inadequate to survey functional connectivity differences associated with a range of neurological disorders where the ROI information may not be available. A second problem encountered in fMRI measures of connectivity is the need for an arbitrary correlation threshold to determine whether or not two areas are connected. This is problematic because in many cases the differences in tissue connectivity between disease groups and/or control subjects are threshold dependent. In this work we propose a novel voxel-based contrast mechanism for rs-fMRI, the intrinsic connectivity distribution (ICD), that neither requires a priori information to define a ROI, nor an arbitrary threshold to define a connection. We show the sensitivity of previous methods to the choice of connection thresholds and evaluate ICD using a survey study comparing young adults born prematurely to healthy term control subjects. Functional connectivity differences were found in hypothesized language processing areas in the left temporal-parietal areas. In addition, significant clinically-relevant differences were found between preterm and term control subjects, highlighting the importance of whole brain surveys independent of a priori information.
静息态功能磁共振成像（rs-fMRI）有望成为一种临床工具，用于描述和监测不同神经和精神疾病的表型。最常用的分析方法需要定义一个或多个感兴趣区域（ROI）。然而，这种对先验 ROI 信息的需求使得 rs-fMRI 不足以调查与一系列神经障碍相关的功能连接差异，因为这些障碍的 ROI 信息可能不可用。在 fMRI 连接性测量中遇到的第二个问题是需要任意相关阈值来确定两个区域是否连接。这是有问题的，因为在许多情况下，疾病组和/或对照组之间的组织连接差异是依赖于阈值的。在这项工作中，我们提出了一种用于 rs-fMRI 的新的基于体素的对比机制，即固有连接分布（ICD），它既不需要先验信息来定义 ROI，也不需要任意阈值来定义连接。我们展示了先前方法对连接阈值选择的敏感性，并使用一项比较早产儿和健康足月对照组的年轻人的研究来评估 ICD。在左侧颞顶区域的假设语言处理区域中发现了功能连接差异。此外，还在早产儿和足月对照组之间发现了具有临床意义的显著差异，突出了独立于先验信息进行全脑调查的重要性。
