Cash David M, Melbourne Andrew, Modat Marc, Cardoso M Jorge, Clarkson Matthew J, Fox Nick C, Ourselin Sebastien
Centre for Medical Image Computing, University College of London, UCL.
Med Image Comput Comput Assist Interv. 2012;15(Pt 3):289-96. doi: 10.1007/978-3-642-33454-2_36.
Cortical thinning is a widely used and powerful biomarker for measuring disease progression in Alzheimer's disease (AD). However, there has been little work on the effect of atrophy on the cortical folding patterns. In this study, we examined whether the cortical folding could be used as a biomarker of AD. Cortical folding metrics were computed on 678 patients from the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort. For each subject, the boundary between grey matter and white matter was extracted using a level set technique. At each point on the boundary two metrics characterising folding, curvedness and shape index, were generated. Joint histograms using these metrics were calculated for five regions of interest (ROIs): frontal, temporal, occipital, and parietal lobes as well as the cingulum. Pixelwise statistical maps were generated from the joint histograms using permutations tests. In each ROI, a significant reduction was observed between controls and AD in areas associated with the sulcal folds, suggesting a sulcal opening associated with neurodegeneration. When comparing to MCI patients, the regions of significance were smaller but overlapping with those regions found comparing controls to AD. It indicates that the differences in cortical folding are progressive and can be detected before formal diagnosis of AD. Our preliminary analysis showed a viable signal in the cortical folding patterns for Alzheimer's disease that should be explored further.
皮质变薄是一种广泛应用且强大的生物标志物，用于测量阿尔茨海默病（AD）的疾病进展。然而，关于萎缩对皮质折叠模式的影响，相关研究较少。在本研究中，我们检验了皮质折叠是否可作为AD的生物标志物。我们对来自阿尔茨海默病神经影像倡议（ADNI）队列的678名患者计算了皮质折叠指标。对于每个受试者，使用水平集技术提取灰质和白质之间的边界。在边界上的每个点生成两个表征折叠的指标，即曲率和形状指数。针对五个感兴趣区域（ROI）：额叶、颞叶、枕叶、顶叶以及扣带回，计算使用这些指标的联合直方图。使用置换检验从联合直方图生成逐像素统计地图。在每个ROI中，在与脑沟褶皱相关的区域观察到对照组和AD组之间存在显著减少，表明与神经退行性变相关的脑沟增宽。与轻度认知障碍（MCI）患者相比，显著区域较小，但与对照组和AD组比较时发现的区域重叠。这表明皮质折叠的差异是渐进性的，并且在AD正式诊断之前就可以检测到。我们的初步分析表明，阿尔茨海默病的皮质折叠模式中存在一个可行的信号，应进一步探索。
