Fu Luke, Fonov Vladimir, Pike Bruce, Evans Alan C, Collins D Louis
McConnell Brain Imaging center, Montreal Neurological Institute, Quebec, Canada.
Med Image Comput Comput Assist Interv. 2006;9(Pt 2):144-51. doi: 10.1007/11866763_18.
In large multi-center studies it is important to quantify data variations due to differences between sites and over time. Here we investigate inter-site variability in signal to noise ratio (SNR), percent integral uniformity (PIU), width and height using the American College of Radiology (ACR) phantom scans from the NIHPD project. Longitudinal variations are also analyzed. All measurements are fully automated. Our results show that the mean SNR, PIU and the 2 metric values were statistically different across sites. The maximum mean difference in diameter across sites was 2 mm (1.1%), and the maximum mean difference in height was 2.5 mm (1.7%). Over time, an average drift of 0.4 mm per year was observed for the diameter while a drift of 0.5 mm per year was observed for the height. Trends observed over time often depended not only on site, but also on modality and scanner manufacturer.
在大型多中心研究中，量化因不同站点和时间差异导致的数据变化非常重要。在此，我们使用来自NIHPD项目的美国放射学会（ACR）体模扫描，研究信噪比（SNR）、积分百分比均匀性（PIU）、宽度和高度的站点间变异性。还分析了纵向变化。所有测量均完全自动化。我们的结果表明，各站点间的平均SNR、PIU和两个度量值在统计学上存在差异。各站点间直径的最大平均差异为2毫米（1.1%），高度的最大平均差异为2.5毫米（1.7%）。随着时间的推移，观察到直径每年平均漂移0.4毫米，而高度每年漂移0.5毫米。随时间观察到的趋势通常不仅取决于站点，还取决于模态和扫描仪制造商。
