Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands.
Hum Brain Mapp. 2010 Dec;31(12):1967-82. doi: 10.1002/hbm.20991. Epub 2010 Apr 16.
Multicenter structural MRI studies can have greater statistical power than single-center studies. However, across-center differences in contrast sensitivity, spatial uniformity, etc., may lead to tissue classification or image registration differences that could reduce or wholly offset the enhanced statistical power of multicenter data. Prior work has validated volumetric multicenter MRI, but robust methods for assessing reliability and power of multisite analyses with voxel-based morphometry (VBM) and cortical thickness measurement (CORT) are not yet available. We developed quantitative methods to investigate the reproducibility of VBM and CORT to detect group differences and estimate heritability when MRI scans from different scanners running different acquisition protocols in a multicenter setup are included. The method produces brain maps displaying information such as lowest detectable effect size (or heritability) and effective number of subjects in the multicenter study. We applied the method to a five-site multicenter calibration study using scanners from four different manufacturers, running different acquisition protocols. The reliability maps showed an overall good comparability between the sites, providing a reasonable gain in sensitivity in most parts of the brain. In large parts of the cerebrum and cortex scan pooling improved heritability estimates, with "effective-N" values upto the theoretical maximum. For some areas, "optimal-pool" maps indicated that leaving out a site would give better results. The reliability maps also reveal which brain regions are in any case difficult to measure reliably (e.g., around the thalamus). These tools will facilitate the design and analysis of multisite VBM and CORT studies for detecting group differences and estimating heritability.
多中心结构磁共振成像研究比单中心研究具有更大的统计学效力。然而，由于对比敏感度、空间均匀性等方面的跨中心差异，可能导致组织分类或图像配准的差异，从而降低或完全抵消多中心数据增强的统计效力。先前的工作已经验证了容积多中心 MRI，但用于评估基于体素形态测量 (VBM) 和皮质厚度测量 (CORT) 的多站点分析的可靠性和效力的稳健方法尚不可用。我们开发了定量方法来研究 VBM 和 CORT 的可重复性，以检测组间差异并估计遗传力，当多中心设置中使用来自不同扫描仪的不同采集协议的 MRI 扫描时。该方法生成显示信息的脑图，例如最低可检测到的效应大小（或遗传力）和多中心研究中的有效受试者数量。我们将该方法应用于一个使用来自四个不同制造商的扫描仪、运行不同采集协议的五个站点的多中心校准研究。可靠性图显示了站点之间的整体良好可比性，在大脑的大部分区域提供了更高的灵敏度增益。在大脑和皮层的大部分区域，扫描池化提高了遗传力估计值，“有效-N”值高达理论最大值。对于某些区域，“最佳池化”图表明排除一个站点会产生更好的结果。可靠性图还揭示了哪些大脑区域无论如何都难以可靠测量（例如，丘脑周围）。这些工具将有助于设计和分析用于检测组间差异和估计遗传力的多站点 VBM 和 CORT 研究。
