Pengas George, Pereira João M S, Williams Guy B, Nestor Peter J
Neurology Unit, Department of Clinical Neurosciences, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
J Neuroimaging. 2009 Jan;19(1):37-46. doi: 10.1111/j.1552-6569.2008.00246.x. Epub 2008 May 19.
Total intracranial volume (TIV) as a measure of premorbid brain size is often used to correct volumes of interest for interindividual differences in magnetic resonance imaging (MRI) studies. We directly compared the reliability of different TIV estimation methods to address whether such methods are influenced by brain atrophy in the neurodegenerative disease, semantic dementia.
We contrasted several manual approaches using T1-weighted, T2-weighted, and proton density (PD) acquisitions with 2 automated methods (statistical parametric mapping 5 [SPM5] and FreeSurfer [FS]) in a cohort of semantic dementia subjects (n= 11) that had been imaged longitudinally.
Novel mid-cranial sampling of either PD or T2-weighted images were least susceptible to atrophy: of these, the PD method was both more precise and more user-friendly. SPM5 also produced good results, providing automation for only a small loss in precision compared to the best manual methods. The T1 method that underestimated TIV as atrophy progressed was the least reproducible and the most labor-intensive. Fully automated FS overestimated TIV with progressive atrophy, and the results were even worse after optimizing the transformation.
The mid-cranial sampling of PD images achieved the best combination of precision, reliability, and user-friendliness. SPM5 is an attractive alternative if the highest level of precision is not required.
在磁共振成像（MRI）研究中，总颅内体积（TIV）作为病前脑大小的一种测量指标，常被用于校正感兴趣区域的体积，以消除个体间差异。我们直接比较了不同TIV估计方法的可靠性，以探讨这些方法是否受神经退行性疾病——语义性痴呆中脑萎缩的影响。
我们在一组纵向成像的语义性痴呆受试者（n = 11）中，将使用T1加权、T2加权和质子密度（PD）采集的几种手动方法与两种自动方法（统计参数映射5 [SPM5]和FreeSurfer [FS]）进行了对比。
PD或T2加权图像的新型中颅采样对萎缩最不敏感：其中，PD方法既更精确又更便于用户使用。SPM5也产生了良好的结果，与最佳手动方法相比，其自动化仅导致精度略有损失。随着萎缩进展而低估TIV的T1方法是可重复性最差且最耗费人力的。完全自动化的FS随着萎缩进展高估了TIV，并且在优化变换后结果更差。
PD图像的中颅采样在精度、可靠性和用户友好性方面实现了最佳组合。如果不需要最高水平的精度，SPM5是一个有吸引力的替代方法。
