Identifying multimodal imaging‐driven subtypes in mild cognitive impairment using deep multiview learning

Abstract

AbstractBackgroundMultimodal neuroimaging data can provide complementary information that a single modality cannot about neurodegenerative diseases such as Alzheimer's disease (AD). Deep Generalized Canonical Correlation Analysis (DGCCA) is able to learn a shared feature representation from different views of data by applying non‐linear transformation using neural network. We utilize DGCCA to extract maximally correlated components from multi‐modal neuroimaging data to identify potential imaging‐driven MCI subtypes.MethodWe study 308 Mild Cognitive Impairment (MCI) participants (195 early MCI and 113 late MCI) from the Alzheimer’s Disease Neuroimaging Initiative (ADNI), each with voxel level features from FDG PET, amyloid PET (AV45) and structural MRI processed using voxel‐based morphometry (VBM). Six experimental settings are designed to compare single modality with multiview methods ‐ GCCA and DGCCA, see Figure 1. Agglomerative clustering was used to generated 2 clusters with features from each experiment. To investigate differences between the clusters, Wilcoxon rank‐sum tests are conducted on 11 baseline AD biomarkers including 5 cognitive assessments and 6 brain volume measures, from the ADNI QT‐PAD dataset http://www.pi4cs.org/qt‐pad‐challenge.ResultAmong the two multiview methods, DGCCA is able to explain 68.57% variance with 20 features, while GCCA explains 68.66% variance with 94 features. To evaluate the potential subtypes from clustering, the Calinski‐Harabasz (CH) score, Silhouette score and adjusted mutual information (AMI) score are computed, see Table 1. AV45 generates the best defined clusters, where DGCCA generates clusters with quality comparable to single modality features. In our QT analysis, clusters from FDG and DGCCA features show differential measure in all biomarkers where DGCCA learns from multimodal data, see Figure 2.ConclusionDGCCA is able to learn maximally correlated features from multimodal neuroimaging data with reduced dimensionality, and explain more variance than its linear counterpart GCCA. Cluster analysis shows these imaging‐driven MCI subtypes are different from the currently diagnosis with differential QT measures, by incorporating complementary information from 3 imaging modalities. DGCCA shows to be an effective feature learning method, and this multiview learning framework can identify potentially novel MCI subtypes to facilitate early detection of AD.