自适应阈值化功能磁共振统计参数映射图

Adaptive Thresholding of Statistical Parametric Map in fMRI

为了准确检测及定位功能激发信息,需选择一个客观、有效的阈值来阈值化功能磁共振统计参数映射图.为此提出了一种组合控制错误发现率及分析皮层血流动力学响应的空间相关性阈值化功能磁共振统计参数映射图的方法.该方法首先采用基于控制错误发现率的方法确定阈值,进行激发体素判别,然后分析已判别为激发的体素与其三维空间26-邻域体素的血流动力学响应的相关性,并进行空间相关检验.该方法不仅能够自适应地选取阈值,而且能够识别由于随机因素而导致的伪激发体素,具有更好脑功能激发信息检测及空间定位能力.

In order to accurately identify and locate the functional active information, an objective and effective threshold must be found to threshold the statistical parametric map of fMRI. This paper reports a method to threshold the statistical parametric map of fMRI, which combines controlling the false discovery rate with analyzing the spatial correlation of the cortical hemodynamic responses. Firstly, for identifying the active voxels, the proposed method determines threshold based on controlling false discovery rate. Secondly, it analyzes and tests the correlation of hemodynamic responses between the identified active voxels and their 26-neighboring voxels. Not only can it select the threshold adaptively, but can identify the false active voxels caused by stochastic factors, with the strong capability of identifying and locating the functional active information. The proposed method is validated by using both simulation study and real fMRI data analysis.