Brain morphometry reproducibility in multi-center 3 T MRI studies: A comparison of cross-sectional and longitudinal segmentations
Brain morphometry reproducibility in multi-center 3 T MRI studies: A comparison of cross-sectional and longitudinal segmentations
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DOI：
10.1016/j.neuroimage.2013.05.007
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发表时间：
2013-12-01
期刊：
影响因子：
5.7
通讯作者：
Frisoni, Giovanni B.
中科院分区：
文献类型：
--
作者：
Jovicich, Jorge;Marizzoni, Moira;Frisoni, Giovanni B.
大规模纵向多部位MRI脑形态测量研究对于使用全自动分割工具表征正常人群和临床人群正变得越来越重要。对于不同的MR供应商，在多个扫描会话中采集的形态测量数据的重复性测试是一个重要的可靠性指标，因为它定义了检测联合体中纵向效应的协议的灵敏度。关于不同的3T MRI系统如何影响跨节段的形态测量估计的可靠性，我们知之甚少。此外，还需要最佳的采集和分析方案，以减少样本量。最近的一项研究表明，与使用非标准多回波MPRAGE序列的一个3T部位的横断面分割相比，纵向自由漂移分割在会话测试中提供了更好的重复性。在这项研究中，我们基于供应商提供的不同供应商(西门子和飞利浦的3D MPRAGE，GE的3D IR-SPGR)的钛结构序列，在4个欧洲国家的8个地点实施了多站点3T MRI形态测量协议。协议在可能的情况下使用了温和的加速系数(1.5-2)。我们获得了一组健康的老年受试者(每个站点5名受试者)的跨时段测试重测结构数据，并比较了两种基于纵向和横截面自由跳跃处理的全脑自动分割方法的跨时段重复性。这些节段包括皮质厚度、颅内、脑室和皮质下体积。重复性的评估是绝对变化相对于平均值(%)，骰子系数的体积重叠和组内相关系数在两个阶段。我们发现，这种采集和分析方案提供了与以前使用更长时间的采集而不加速的研究类似的重复性结果。我们还表明，无论MRI系统的差异如何，纵向处理在系统上跨站点都更可靠。对于所有体积分段和内嗅皮层厚度，纵向分段的重复性误差平均约为横断面分析的一半。对于其他皮质厚度估计，在分割方法之间没有发现显著的可靠性差异。在每一次重测期间获得的平均两个MPRAGE体积并没有系统地改善形态计量估计的跨会场再现性。我们的结果扩展了以前的研究，这些研究表明在单一地点和/或使用非标准获取方法的纵向分析的可靠性得到了改善。这里提出的多部位采集和分析方案在临床应用中很有前景，因为它允许每个MRI部位的样本量更小，或者在评估潜在生物标记物在预测疾病进展或治疗效果方面的作用的研究中允许进行更短的试验。(C)2013 Elsevier Inc.保留所有权利。
Large-scale longitudinal multi-site MRI brain morphometry studies are becoming increasingly crucial to characterize both normal and clinical population groups using fully automated segmentation tools. The test retest reproducibility of morphometry data acquired across multiple scanning sessions, and for different MR vendors, is an important reliability indicator since it defines the sensitivity of a protocol to detect longitudinal effects in a consortium. There is very limited knowledge about how across-session reliability of morphometry estimates might be affected by different 3 T MRI systems. Moreover, there is a need for optimal acquisition and analysis protocols in order to reduce sample sizes. A recent study has shown that the longitudinal FreeSurfer segmentation offers improved within session test retest reproducibility relative to the cross-sectional segmentation at one 3 T site using a nonstandard multi-echo MPRAGE sequence. In this study we implement a multi-site 3 T MRI morphometry protocol based on vendor provided Ti structural sequences from different vendors (3D MPRAGE on Siemens and Philips, 3D IR-SPGR on GE) implemented in 8 sites located in 4 European countries. The protocols used mild acceleration factors (1.5-2) when possible. We acquired across-session test retest structural data of a group of healthy elderly subjects (5 subjects per site) and compared the across-session reproducibility of two full-brain automated segmentation methods based on either longitudinal or cross-sectional FreeSurfer processing. The segmentations include cortical thickness, intracranial, ventricle and subcortical volumes. Reproducibility is evaluated as absolute changes relative to the mean (%), Dice coefficient for volume overlap and intraclass correlation coefficients across two sessions. We found that this acquisition and analysis protocol gives comparable reproducibility results to previous studies that used longer acquisitions without acceleration. We also show that the longitudinal processing is systematically more reliable across sites regardless of MRI system differences. The reproducibility errors of the longitudinal segmentations are on average approximately half of those obtained with the cross sectional analysis for all volume segmentations and for entorhinal cortical thickness. No significant differences in reliability are found between the segmentation methods for the other cortical thickness estimates. The average of two MPRAGE volumes acquired within each test-retest session did not systematically improve the across-session reproducibility of morphometry estimates. Our results extend those from previous studies that showed improved reliability of the longitudinal analysis at single sites and/or with non-standard acquisition methods. The multi-site acquisition and analysis protocol presented here is promising for clinical applications since it allows for smaller sample sizes per MRI site or shorter trials in studies evaluating the role of potential biomarkers to predict disease progression or treatment effects. (C) 2013 Elsevier Inc. All rights reserved.