Effect of scanner in asymmetry studies using diffusion tensor imaging
Effect of scanner in asymmetry studies using diffusion tensor imaging
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DOI：
10.1016/j.neuroimage.2010.09.023
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发表时间：
2011-01
期刊：
影响因子：
5.7
通讯作者：
H. Takao;N. Hayashi;K. Ohtomo
中科院分区：
文献类型：
--
作者：
H. Takao;N. Hayashi;K. Ohtomo
本研究的目的是利用同一机构的两台完全相同型号的扫描仪获得的纵向数据，评估扫描仪硬件的纵向漂移、扫描仪间的变异性(BIAS)和扫描仪升级对扩散特性不对称性的影响。本研究共纳入224名正常受试者(63名女性和161名男性)。每个受试者使用两台完全相同型号的3.0-T扫描仪进行两次扫描，扫描间隔约为1年(平均间隔=1.0±0.11年，范围=0.6~1.3年)。两台扫描仪在研究期间同时进行了升级(159名受试者在升级前接受了后续扫描，其余65名受试者在升级后进行了后续扫描)。受试者根据所用扫描仪的组合被分成4组。利用基于区域的空间统计方法，研究了扫描仪漂移和扫描仪间变异性对分数各向异性(FA)和平均扩散率(MD)不对称性的影响。我们还研究了扫描仪升级对FA和MD不对称性的影响。体素分析显示，在不同扫描仪上获得基线和随访图像的组中，有许多区域的FA和MD不对称性具有显著的纵向变化。即使使用完全相同型号的扫描仪，扫描仪间的变异性(BIAS)也会显著影响FA和MD的不对称性，这两种不对称性在同一扫描仪中相对稳定。扫描仪升级对FA和MD的不对称性影响不大。结果表明，多台扫描仪的使用增加了DTI非对称性测量的可变性，并可能影响横断面尤其是纵向DTI非对称性研究的结果。
The purpose of this study was to evaluate the effects of longitudinal drift in scanner hardware, inter-scanner variability (bias) and scanner upgrade on asymmetries of diffusion properties using longitudinal data obtained on two scanners of the exact same model at one institution. A total of 224 normal subjects (63 females and 161 males) were included in this study. Each subject was scanned twice, at an interval of about 1year (mean interval=1.0±0.11years, range=0.6–1.3years), using two 3.0-T scanners of the exact same model. Both scanners were simultaneously upgraded during the study period (159 subjects underwent a follow-up scan before upgrade, and the remaining 65 subjects underwent a follow-up scan after upgrade). The subjects were divided into 4 groups according to the combination of scanners used. With the use of tract-based spatial statistics (TBSS), we investigated the effects of scanner drift and inter-scanner variability (bias) on asymmetries of fractional anisotropy (FA) and mean diffusivity (MD). We also investigated the effect of scanner upgrade on FA and MD asymmetries. The voxel-wise analyses revealed a number of regions with significant longitudinal changes in FA and MD asymmetries in the groups where baseline and follow-up images were obtained on different scanners. Even with scanners of the exact same model, inter-scanner variability (bias) significantly affected FA and MD asymmetries, which were relatively stable within the same scanner. Scanner upgrade had a small effect on FA and MD asymmetries. The results indicate that the use of multiple scanners increases variability of DTI asymmetry measurements, and can affect the results of cross-sectional and especially longitudinal DTI asymmetry studies.