Malone Ian B, Leung Kelvin K, Clegg Shona, Barnes Josephine, Whitwell Jennifer L, Ashburner John, Fox Nick C, Ridgway Gerard R
Dementia Research Centre (DRC), Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
Dementia Research Centre (DRC), Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
Neuroimage. 2015 Jan 1;104:366-72. doi: 10.1016/j.neuroimage.2014.09.034. Epub 2014 Oct 1.
Total intracranial volume (TIV/ICV) is an important covariate for volumetric analyses of the brain and brain regions, especially in the study of neurodegenerative diseases, where it can provide a proxy of maximum pre-morbid brain volume. The gold-standard method is manual delineation of brain scans, but this requires careful work by trained operators. We evaluated Statistical Parametric Mapping 12 (SPM12) automated segmentation for TIV measurement in place of manual segmentation and also compared it with SPM8 and FreeSurfer 5.3.0. For T1-weighted MRI acquired from 288 participants in a multi-centre clinical trial in Alzheimer's disease we find a high correlation between SPM12 TIV and manual TIV (R(2)=0.940, 95% Confidence Interval (0.924, 0.953)), with a small mean difference (SPM12 40.4±35.4ml lower than manual, amounting to 2.8% of the overall mean TIV in the study). The correlation with manual measurements (the key aspect when using TIV as a covariate) for SPM12 was significantly higher (p<0.001) than for either SPM8 (R(2)=0.577 CI (0.500, 0.644)) or FreeSurfer (R(2)=0.801 CI (0.744, 0.843)). These results suggest that SPM12 TIV estimates are an acceptable substitute for labour-intensive manual estimates even in the challenging context of multiple centres and the presence of neurodegenerative pathology. We also briefly discuss some aspects of the statistical modelling approaches to adjust for TIV.
总颅内体积（TIV/ICV）是大脑及脑区体积分析的重要协变量，尤其在神经退行性疾病研究中，它可作为病前最大脑体积的替代指标。金标准方法是对脑部扫描进行手动勾勒，但这需要训练有素的操作人员仔细操作。我们评估了用统计参数映射12（SPM12）自动分割来测量TIV以替代手动分割，并将其与SPM8和FreeSurfer 5.3.0进行比较。对于在一项多中心阿尔茨海默病临床试验中从288名参与者获取的T1加权磁共振成像，我们发现SPM12测量的TIV与手动测量的TIV之间具有高度相关性（R² = 0.940，95%置信区间（0.924，0.953）），平均差异较小（SPM12比手动测量低40.4±35.4毫升，占研究中总体平均TIV的2.8%）。SPM12与手动测量值（将TIV用作协变量时的关键方面）的相关性显著高于SPM8（R² = 0.577，置信区间（0.500，0.644））或FreeSurfer（R² = 0.801，置信区间（0.744，0.843））（p<0.001）。这些结果表明，即使在多中心且存在神经退行性病变这种具有挑战性的情况下，SPM12对TIV的估计也是劳动密集型手动估计的可接受替代方法。我们还简要讨论了针对TIV进行调整的统计建模方法的一些方面。
