Evaluation of Brain Tortuosity Measurement for the Automatic Multimodal Classification of Subjects with Alzheimerxe2x80x99s Disease The 3D tortuosity determined in several brain areas is proposed as a new morphological biomarker (BM) to be considered in early detection of Alzheimerxe2x80x99s disease (AD). It is measured using the sum of angles method and it has proven to be sensitive to anatomical changes that appear in gray and white matter and temporal and parietal lobes during mild cognitive impairment (MCI). Statistical analysis showed significant differences (                     )  between tortuosity indices determined for healthy controls (HC) vs. MCI and HC vs. AD in most of the analyzed structures. Other clinically used BMs have also been incorporated in the analysis: betaamyloid and tau protein CSF and plasma concentrations, as well as other imageextracted parameters. A classification strategy using random forest (RF) algorithms was implemented to discriminate between three samples of the studied populations, selected from the ADNI database. Classification rates considering only imageextracted parameters show an increase of 9.17%, when tortuosity is incorporated. An enhancement of 1.67% is obtained when BMs measured from several modalities are combined with tortuosity.

Topological Characterization of the Multifeature based Network in Patients with Alzheimers Disease and Mild Cognitive Impairment Characterization of morphological organization pattern in individual brain has long been an open question. Recently, a novel singlesubject network that built upon multiple morphological features (MFN) was introduced 1, which exhibited extraordinary power in diagnosing patients with Alzheimeru0027s disease (AD) and mild cognitive impairment (MCI). This study aims to characterize the corticocortical topological organization in MCI and AD cohorts via the MFN, and uncover the structural substrate that leads to the high classification accuracy. The MFNs were constructed for 165 normal controls (NCs), 221 patients with MCI, and 142 patients with AD from the Alzheimeru0027s Disease Neuroimaging Initiative (ADNI). Results from graph theoretical analysis showed xe2x80x98smallworldxe2x80x99 property and modular organization of the MFN in three groups; as well as increased local clustering and characteristic path length, and altered hub regions in patients with AD and MCI. More importantly, we found the primary atrophic regions were accompanied by increased number of inflow connections; whereas, the connections that linked to the less atrophic regions were mostly outflow connections. This phenomenon, we speculated, might indirectly reflect the trophic supporting effects in the brain. Our results demonstrated the basic organizational principles of the MFN and its changes in patients with AD and MCI, providing important implications of what makes the MFN powerful in autodiagnosis of mental disorders.