Global, voxel, and cluster tests, by theory and permutation, for a difference between two groups of structural MR images of the brain
Global, voxel, and cluster tests, by theory and permutation, for a difference between two groups of structural MR images of the brain
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DOI：
10.1109/42.750253
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发表时间：
1999-01-01
影响因子：
10.6
通讯作者：
Brammer, MJ
中科院分区：
文献类型：
--
作者：
Bullmore, ET;Suckling, J;Brammer, MJ
我们描述了用于估计全局、体素和簇级统计数据的几乎完全自动化的程序，以测试两组结构磁共振成像（MRI）数据之间零神经解剖学差异的零假设。原假设下的理论分布可用于 1) 全局组织类别体积； 2）标准化线性模型[方差分析（ANOVA和ANCOVA）]每个体素估计的系数； 3）通过将任意阈值应用于体素级别的正常统计的二维（2-D）图来生成空间连接的簇的区域。我们描述了通过观察数据的排列，在零假设下经济地确定概率分布的新方法，用更少的假设。通过排列测试进行的标称 I 类错误控制通常非常好；而理论分布可能过于保守。排列还有一个额外的优点，即它可以用于测试任何感兴趣的统计量，例如簇（或簇质量）中阈上体素统计量的总和，而不管其在原假设下的理论可处理性如何。这些问题通过应用从 18 名多动症青少年和 16 名年龄和性别匹配的对照受试者获得的 MRI 数据来说明。
We describe almost entirely automated procedures for estimation of global, voxel, and cluster-level statistics to test the null hypothesis of zero neuroanatomical difference between two groups of structural magnetic resonance imaging (MRI) data. Theoretical distributions under the null hypothesis are available for 1) global tissue class volumes; 2) standardized linear model [analysis of variance (ANOVA and ANCOVA)] coefficients estimated at each voxel; and 3) an area of spatially connected clusters generated by applying an arbitrary threshold to a two-dimensional (2-D) map of normal statistics at voxel level. We describe novel methods for economically ascertaining probability distributions under the null hypothesis, with fewer assumptions, by permutation of the observed data. Nominal Type I error control by permutation testing is generally excellent; whereas theoretical distributions may be over conservative. permutation has the additional advantage that it can be used to test any statistic of interest, such as the sum of suprathreshold voxel statistics in a cluster (or cluster mass), regardless of its theoretical tractability under the null hypothesis. These issues are illustrated by application to MRI data acquired from 18 adolescents with hyperkinetic disorder and 16 control subjects matched for age and gender.