Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, Scientific Institute and University Hospital San Raffaele, 20132 Milan, Italy.
J Magn Reson Imaging. 2010 Jun;31(6):1458-68. doi: 10.1002/jmri.22186.
To assess the effect on diffusion tensor (DT) magnetic resonance imaging (MRI) of acquiring data with different scanners.
Forty-four healthy controls and 36 multiple sclerosis patients with low disability were studied using eight MR scanners with acquisition protocols that were as close to a standard protocol as possible. Between 7 and 13 subjects were studied in each center. Region-of-interest (ROI) and histogram-based analyses of fractional anisotropy (FA), axial (D(ax)), radial (D(rad)), and mean diffusivity (MD) were performed. The influence of variables such as the acquisition center and the control/patient group was determined with an analysis of variance (ANOVA) test.
The patient/control group explained approximately 25% of data variability of FA and D(rad) from midsagittal corpus callosum (CC) ROIs. Global FA, MD, and D(rad) in the white matter differentiated patients from controls, but with lower discriminatory power than for the CC. In the gray matter, MD discriminated patients from controls (30% of variability explained by group vs. 17% by center).
Significant variability of DT-MRI data can be attributed to the acquisition center, even when a standardized protocol is used. The use of appropriate segmentation methods and statistical models allows DT-derived metrics to differentiate patients from healthy controls.
评估使用不同扫描仪获取数据对扩散张量（DT）磁共振成像（MRI）的影响。
使用 8 台磁共振扫描仪对 44 名健康对照者和 36 名低残疾多发性硬化症患者进行了研究，这些扫描仪的采集方案尽可能接近标准方案。每个中心都有 7 到 13 名受试者接受了研究。对各向异性分数（FA）、轴向（D（ax））、径向（D（rad））和平均弥散度（MD）的感兴趣区域（ROI）和基于直方图的分析进行了评估。采用方差分析（ANOVA）检验确定了采集中心和对照/患者组等变量的影响。
患者/对照组约解释了 FA 和 D（rad）从正中矢状胼胝体（CC）ROI 数据变异性的 25%。大脑白质的整体 FA、MD 和 D（rad）可以区分患者和对照者，但 CC 的区分能力较低。在灰质中，MD 可以区分患者和对照者（组解释的变异性为 30%，而中心为 17%）。
即使使用标准化方案，DT-MRI 数据的显著变异性也可能归因于采集中心。使用适当的分割方法和统计模型可以使 DT 衍生指标区分患者和健康对照者。
