Multiple Diffusion Indices Reveals White Matter Degeneration in Alzheimer's Disease and Mild Cognitive Impairment: A Tract-Based Spatial Statistics Study

Issue title: Imaging the Alzheimer Brain

Guest editors: J. Wesson Ashford, Allyson Rosen, Maheen Adamson, Peter Bayley, Osama Sabri, Ansgar Furst, Sandra E. Black and Michael Weiner

Article type: Research Article

Authors: Shu, Ni^{a; 1} | Wang, Zhiqun^{b; 1} | Qi, Zhigang^b | Li, Kuncheng^{b; c; *} | He, Yong^{a; *}

Affiliations: [a] State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China | [b] Department of Radiology, Xuanwu Hospital of Capital Medical University, Beijing, China | [c] Key Laboratory for Neurodegenerative Diseases (Capital Medical University), Ministry of Education, Beijing, China

Correspondence: [*] Correspondence to: Yong He, Ph.D, State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875, China. Tel.: +86 10 5880 2036; E-mail: [email protected] and Kuncheng Li, M.D., Department of Radiology, Xuanwu Hospital of Capital Medical University, Beijing 100053, China. Tel.: +86 10 8319 8376; E-mail: [email protected].

Note: [1] These authors contributed equally to this work.

Abstract: Alzheimer's disease (AD) is a progressive neurodegenerative disease involving the decline of memory and other cognitive functions. Mild cognitive impairment (MCI) represents a transition phase between normal aging and early AD. The degeneration patterns of the white matter across the brain in AD and MCI remain largely unclear. Here we used diffusion tensor imaging and tract-based spatial statistics (TBSS) to investigate white matter changes in multiple diffusion indices (e.g., fractional anisotropy, axial, radial and mean diffusivities) in both AD and MCI patients. Compared with the normal controls, the AD patients had reduced fractional anisotropy and increased axial, radial and mean diffusivities in widespread white matter structures, including the corpus callosum and the white matter of lateral temporal cortex, the posterior cingulate cortex/precuneus and the fronto-parietal regions. Similar white matter regions with reduced anisotropy were also found in MCI patients but with a much less extent than in AD. Between the AD and MCI groups, there were significant differences in the axial and mean diffusivities of the white matter tracts adjacent to the posterior cingulate cortex/precuneus without anisotropy changes. Taken together, our findings based upon multiple diffusion indices (FA, axial, radial and mean diffusivities) suggest distinct degeneration behaviors of the white matter in AD and MCI.

Keywords: Connectivity, axial diffusivity, radial diffusivity, DTI, TBSS

DOI: 10.3233/JAD-2011-0024

Journal: Journal of Alzheimer's Disease, vol. 26, no. s3, pp. 275-285, 2011