Joshi Anand A, Chong Minqi, Leahy Richard M
Signal and Image Processing Institute, University of Southern California, USA.
Med Image Comput Comput Assist Interv. 2017 Sep;10433:486-494. doi: 10.1007/978-3-319-66182-7_56. Epub 2017 Sep 4.
We describe a method that allows direct comparison of resting fMRI (rfMRI) time series across subjects. For this purpose, we exploit the geometry of the rfMRI signal space to conjecture the existence of an orthogonal transformation that synchronizes fMRI time series across sessions and subjects. The method is based on the observation that rfMRI data exhibit similar connectivity patterns across subjects, as reflected in the pairwise correlations between different brain regions. The orthogonal transformation that performs the synchronization is unique, invertible, efficient to compute, and preserves the connectivity structure of the original data for all subjects. Similarly to image registration, where we spatially align the anatomical brain images, this synchronization of brain signals across a population or within subject across sessions facilitates longitudinal and cross-sectional studies of rfMRI data. The utility of this transformation is illustrated through applications to quantification of fMRI variability across subjects and sessions, joint cortical clustering of a population and comparison of task-related and resting fMRI.
我们描述了一种方法，该方法允许对不同受试者的静息功能磁共振成像（rfMRI）时间序列进行直接比较。为此，我们利用rfMRI信号空间的几何结构来推测存在一种正交变换，该变换可使不同时段和受试者的fMRI时间序列同步。该方法基于这样的观察结果：rfMRI数据在不同受试者之间表现出相似的连通性模式，这反映在不同脑区之间的成对相关性中。执行同步的正交变换是唯一的、可逆的、计算效率高的，并且保留了所有受试者原始数据的连通性结构。类似于我们在空间上对齐解剖学脑图像的图像配准，这种跨群体或受试者内不同时段的脑信号同步有助于对rfMRI数据进行纵向和横断面研究。通过将该变换应用于量化不同受试者和时段的fMRI变异性、群体的联合皮质聚类以及任务相关和静息fMRI的比较，说明了该变换的实用性。
