Multi-modal tensor representations of brain networks

Abstract

Considering the economic, social and psychological burdens of Alzheimer’s disease (AD), the most common form of dementia, it is essential to gain insight into the process and underlying mechanisms of the disease. Using structural and functional brain connectomes obtained by in-vivo MRI techniques as biomarkers is a promising approach. In this thesis, the B-Tensor structure that allows the representation of brain connectomes defined in structurally and functionally with a uni-modal and multi-modal fashion is presented. With the projection of structural connectomes onto known func tional networks, patients with AD and healthy control group are distinguished in a 7-dimensional space with a separation performance of over 90%. In addition, with the uni-modal and multi-modal tensor factorization methods, 47 patients with different levels of AD, are diagnosed with an accuracy of 77% - 100% in a 5-dimensional space. The results show that the multi-modal factorization technique performs better than the uni-modal one by successfully fusing the structural and functional networks which offer complementary information. While the neurological evaluations of the obtained sub-networks are highly consistent with previous literature, new findings regarding the progression of the disease are also recommended.