Reducing interscanner variability of activation in a multicenter fMRI study: Controlling for signal-to-fluctuation-noise-ratio (SFNR) differences
Reducing interscanner variability of activation in a multicenter fMRI study: Controlling for signal-to-fluctuation-noise-ratio (SFNR) differences
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DOI：
10.1016/j.neuroimage.2006.07.012
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发表时间：
2006-11-01
期刊：
影响因子：
5.7
通讯作者：
Glover, Gary H.
中科院分区：
文献类型：
--
作者：
Friedman, Lee;Glover, Gary H.
在多中心fMRI研究中，扫描仪性能的变化将导致激活模式的变化。本研究的目的是评估信号与波动噪声比（SFNR）扫描仪差异的统计学协变对减少激活效应大小扫描仪差异的影响，作为多中心fMRI项目（FIRST BIRN）的一部分。对于SFNR，“信号”通常是随时间的平均强度，而“波动噪声”是时间标准偏差。5名受试者被送往9个中心（10台扫描仪），并使用感觉运动功能磁共振成像协议连续两天进行扫描。包括来自三家供应商（GE、Siemens和Picker）的高场（4 T和3 T）和低场（1.5 T）扫描仪。在感觉运动任务期间检测神经激活的效应量被评估为我们的模型占时间方差的百分比（占方差的百分比，或PVAF）。PVAF和SFNR均观察到明显的扫描仪效应。在用SFNR的几种测量方法之一进行协变量调整后，激活效应大小的扫描仪到扫描仪变化显著减少。方差分量分析表明，75%-81%的方差减少，由于扫描仪与这种方法。因此，在多中心研究中，控制SFNR中的扫描仪变化可能是均匀化激活效应大小的有效方法。(c)2006年爱思唯尔公司All rights reserved.
Variation in scanner performance will lead to variation in activation patterns in multicenter fMRI studies. The purpose of this investigation was to evaluate the effect of statistically covarying for scanner differences in signal-to-fluctuation-noise-ratio (SFNR) on reducing scanner differences in activation effect size as part of a multicenter fMRI project (FIRST BIRN). For SFNR, "signal" is typically the mean intensity over time and "fluctuation noise" is the temporal standard deviation. Five subjects were sent to 9 centers (10 scanners) and scanned on two consecutive days using a sensorimotor fMRI protocol. High-field (4 T and 3 T) and low-field (1.5 T) scanners from three vendors (GE, Siemens and Picker) were included. The effect size for the detection of neural activation during a sensorimotor task was evaluated as the percent of temporal variance accounted for by our model (percent of variance accounted for, or PVAF). Marked scanner effects were noted for both PVAF as well as SFNR. After covariate adjustment with one of several measures of SFNR, there were dramatic reductions in scanner-to-scanner variations in activation effect size. Variance components analyses revealed 75%-81% reductions in variance due to scanner with this method. Thus, controlling for scanner variation in SFNR may he an effective method to homogenize activation effect sizes in multicenter studies. (c) 2006 Elsevier Inc. All rights reserved.