Friedman Lee, Stern Hal, Brown Gregory G, Mathalon Daniel H, Turner Jessica, Glover Gary H, Gollub Randy L, Lauriello John, Lim Kelvin O, Cannon Tyrone, Greve Douglas N, Bockholt Henry Jeremy, Belger Aysenil, Mueller Bryon, Doty Michael J, He Jianchun, Wells William, Smyth Padhraic, Pieper Steve, Kim Seyoung, Kubicki Marek, Vangel Mark, Potkin Steven G
Department of Psychiatry and Human Behavior, University of California Irvine, Irvine, California, USA.
Hum Brain Mapp. 2008 Aug;29(8):958-72. doi: 10.1002/hbm.20440.
In the present report, estimates of test-retest and between-site reliability of fMRI assessments were produced in the context of a multicenter fMRI reliability study (FBIRN Phase 1, www.nbirn.net). Five subjects were scanned on 10 MRI scanners on two occasions. The fMRI task was a simple block design sensorimotor task. The impulse response functions to the stimulation block were derived using an FIR-deconvolution analysis with FMRISTAT. Six functionally-derived ROIs covering the visual, auditory and motor cortices, created from a prior analysis, were used. Two dependent variables were compared: percent signal change and contrast-to-noise-ratio. Reliability was assessed with intraclass correlation coefficients derived from a variance components analysis. Test-retest reliability was high, but initially, between-site reliability was low, indicating a strong contribution from site and site-by-subject variance. However, a number of factors that can markedly improve between-site reliability were uncovered, including increasing the size of the ROIs, adjusting for smoothness differences, and inclusion of additional runs. By employing multiple steps, between-site reliability for 3T scanners was increased by 123%. Dropping one site at a time and assessing reliability can be a useful method of assessing the sensitivity of the results to particular sites. These findings should provide guidance toothers on the best practices for future multicenter studies.
在本报告中，功能磁共振成像（fMRI）评估的重测信度和不同站点间信度估计是在一项多中心fMRI信度研究（FBIRN第一阶段，www.nbirn.net）的背景下得出的。五名受试者在10台磁共振成像（MRI）扫描仪上接受了两次扫描。fMRI任务是一个简单的组块设计感觉运动任务。使用FMRISTAT通过有限脉冲响应（FIR）反卷积分析得出对刺激组块的脉冲响应函数。使用了根据先前分析创建的六个功能衍生的感兴趣区域（ROI），覆盖视觉、听觉和运动皮层。比较了两个因变量：信号变化百分比和对比噪声比。信度通过方差成分分析得出的组内相关系数进行评估。重测信度较高，但最初不同站点间信度较低，表明站点以及站点与受试者交互作用产生的方差贡献很大。然而，发现了一些可以显著提高不同站点间信度的因素，包括增大ROI的大小、调整平滑度差异以及增加额外的扫描次数。通过采取多个步骤，3T扫描仪的不同站点间信度提高了123%。一次去掉一个站点并评估信度可能是一种评估结果对特定站点敏感性的有用方法。这些发现应为其他人未来多中心研究的最佳实践提供指导。
