Cai Leon Y, Rheault Francois, Kerley Cailey I, Aboud Katherine S, Beason-Held Lori L, Shafer Andrea T, Resnick Susan M, Jordan Lori C, Anderson Adam W, Schilling Kurt G, Landman Bennett A
Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA.
Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN, USA.
Proc SPIE Int Soc Opt Eng. 2022 Feb-Mar;12032. doi: 10.1117/12.2611562. Epub 2022 Apr 4.
Characterizing relationships between gray matter (GM) and white matter (WM) in early Alzheimer's disease (AD) would improve understanding of how and when AD impacts the brain. However, modeling these relationships across brain regions and longitudinally remains a challenge. Thus, we propose extending joint independent component analysis (jICA) into spatiotemporal modeling of regional cortical thickness and WM bundle volumes leveraging multimodal MRI. We jointly characterize these GM and WM features in a normal aging (n=316) and an age- and sex-matched preclinical AD cohort (n=81) at each of two imaging sessions spaced three years apart, training on the normal aging population in cross-validation and interrogating the preclinical AD cohort. We find this joint model identifies reproducible, longitudinal changes in GM and WM between the two imaging sessions and that these changes are associated with preclinical AD and are plausible considering the literature. We compare this joint model to two focused models: (1) GM features at the first session and WM at the second and (2) vice versa. The joint model identifies components that correlate poorly with those from the focused models, suggesting the different models resolve different patterns. We find the strength of association with preclinical AD is improved in the GM to WM model, which supports the hypothesis that medial temporal and frontal thinning precedes volume loss in the uncinate fasciculus and inferior anterior-posterior association fibers. These results suggest that jICA effectively generates spatiotemporal hypotheses about GM and WM in preclinical AD, especially when specific intermodality relationships are considered .
表征早期阿尔茨海默病（AD）中灰质（GM）与白质（WM）之间的关系，将有助于更好地理解AD如何以及何时影响大脑。然而，对这些跨脑区及纵向关系进行建模仍然是一项挑战。因此，我们建议将联合独立成分分析（jICA）扩展到利用多模态磁共振成像（MRI）对区域皮质厚度和WM束体积进行时空建模。我们在间隔三年的两次成像检查中，对正常衰老人群（n = 316）和年龄及性别匹配的临床前AD队列（n = 81）的GM和WM特征进行联合表征，在交叉验证中以正常衰老人群为训练对象，并对临床前AD队列进行研究。我们发现，这种联合模型能够识别出两次成像检查之间GM和WM中可重复的纵向变化，并且这些变化与临床前AD相关，从文献角度来看也是合理的。我们将这种联合模型与两种聚焦模型进行比较：（1）第一次检查时的GM特征和第二次检查时的WM特征，以及（2）反之亦然。联合模型识别出的成分与聚焦模型中的成分相关性较差，这表明不同模型解析出了不同的模式。我们发现，GM - WM模型中与临床前AD的关联强度有所提高，这支持了内侧颞叶和额叶变薄先于钩束和下前后联合纤维体积减少的假说。这些结果表明，jICA有效地生成了关于临床前AD中GM和WM的时空假说，尤其是在考虑特定的模态间关系时。
