Department of Biomedical Engineering, University of California, Irvine, CA 92697-2755, USA.
Neuroimage. 2010 Feb 1;49(3):2123-33. doi: 10.1016/j.neuroimage.2009.11.006. Epub 2009 Nov 12.
Morphometry of brain structures based on magnetic resonance imaging (MRI) data has become an important tool in neurobiology. Recent multicenter studies in neurodegenerative diseases raised the issue of the precision of volumetric measures, and their dependence on the scanner properties and imaging protocol. A large dataset consisting of 1073 MRI examinations in 843 subjects, acquired on 90 scanners at 58 sites, is analyzed here. A comprehensive set of image quality and content measures is used to describe the influence of the scanner hardware and imaging protocol on the variability of morphometric measures. Scanners equipped with array coils show a remarkable advantage over conventional coils in terms of image quality measures. The signal- and contrast-to-noise ratio in similar systems is equal or slightly better at 1.5 T than 3.0 T, while the white/grey matter tissue contrast is generally better on high-field systems. Repeated MRI investigations on the same scanner were available in 41 subjects, on different scanners in 172 subjects. The retest reliability of repeated volumetric measures under the same conditions was found as sufficient to track changes in longitudinal examinations in individual subjects. Using different acquisition conditions in the same subject, however, the variance of volumetric measures was up to 10 times greater. Two likely factors explaining this finding are scanner-dependent geometrical inaccuracies and differences in the white/grey matter tissue contrast.
基于磁共振成像 (MRI) 数据的脑结构形态计量学已成为神经生物学的重要工具。最近在神经退行性疾病方面的多中心研究提出了容积测量精度的问题，以及它们对扫描仪特性和成像方案的依赖性。本研究分析了一个由 843 名受试者的 1073 次 MRI 检查组成的大型数据集，这些检查是在 58 个地点的 90 台扫描仪上采集的。使用一套全面的图像质量和内容度量标准来描述扫描仪硬件和成像方案对形态计量测量变异性的影响。配备阵列线圈的扫描仪在图像质量度量方面与传统线圈相比具有显著优势。在类似系统中，1.5 T 的信号和对比噪声比与 3.0 T 相等或略好，而高场系统的白/灰质组织对比度通常更好。在 41 名受试者的同一扫描仪上进行了重复 MRI 研究，在 172 名受试者的不同扫描仪上进行了重复 MRI 研究。在相同条件下，重复容积测量的复测可靠性被发现足以在个体受试者的纵向检查中跟踪变化。然而，在同一受试者中使用不同的采集条件，容积测量的方差最大可达 10 倍。有两个可能的因素可以解释这一发现，即扫描仪相关的几何精度差异和白/灰质组织对比度的差异。
