Danqing Xiao

Title : White Matter integrity and key structures affected in Alzheimer’s disease based on diffusion tensor imaging

Abstract:

White matter (WM) degeneration is suggested to predict the early signs of Alzheimer disease (AD). The exact structure regions of brain circuitry involved is not clear. This study aims to examine the associations between WM tract integrity, specifically the specific diffusion tensor imaging (DTI) measures, and AD diagnosis, and denote the key substrate in predicting AD by DTI. This study included four DTI measures, including mean diffusivity (MD), fractional anisotrophy (FA), radial diffusivity (RD) and axial diffusivity (AxD) in 18 main white fiber tract regions measured in 84 non-Hispanic white participants (42 AD patients and 42 controls) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset. The multivariable general linear model (GLM) was used to examine the association of AD diagnosis with each DTI measure adjusting for age, gender, and education. The fornix, corpus callosum, anterior corona radiata, and cingulum hippocampus, right uncinate fasciculus, right superior fronto-occipital fasciculus, left inferior fronto-occipital fasciculus, left sagittal striatum, and posterior thalamic radiation showed significant increases in MD, RD and AxD and decreases in FA among AD patients. Females had lower MD values in certain brain regions and elder people had higher MD values in most DTI measures. Variable cluster analysis identified that hippocampus volume (HPV), mini mental state exam (MMSE), cingulate gyrus/hippocampus (CGC and CGH), inferior fronto-occipital fasciculus IFO and uncinate fasciculus (UNC) are highly correlated in one cluster with DTI measures in MD measures, suggesting these WM tracts are highly connected than other regions (such as SFO) among DTI measures in MD. In conclusion, there were significant differences in most DTI measures between AD and controls. Right cingulum gyrus and right uncinate fasciculus, are particularly affected in cognitive test MMSE for dementia in AD patients and could be the biomarker for predicting AD.

What will audience learn from your presentation?

• The findings will prompt the clinician to use DTI measure for early detection of the onset of Alzheimer’s disease
• The white matter tracts of focus based on cluster analysis are right cingulate gyrus and the right uncinate fasciculus, likely the regions triggering the conversion to AD from non-symptomatic control or mild cognitive impairment individuals
• This research helped the view of AD from the connective point of view of the WM connectivity being the source of pathogenesis. Among the WM tracts, right hemisphere is particularly involved in macroscopic structure changes and cognitive functions including short uncinate fasciculus and the long cingulate gyrus.
• Aging is still the main risk factors associated with AD, not gender or education level.

Biography:

Dr. Xiao studied Biology at Henan Normal University, China and graduated as BS in 1990. She then studied Biochemistry/Entomology at Chinese Academy of Science, Institute of Zoology, China and graduated as MS in 1993. She then studied Pharmacology at Upstate Medical University, Syracuse, USA and graduated as MS in 1997. She received her PhD of Neuroscience at Boston University, USA in 2003. After 2 year postdoctoral fellowship supervised by Dr. Bertha Madras at Harvard Medical School and 3 years postdoctoral fellowship supervised by Dr. Michale Schwarzschild at Massachussets General Hospital, USA,  she obtained the Instructor position of Neurology at MGH. She then studied MRI imaging at MCPHS University, USA and graduated as BS in 2012. She then joined MCPHS and Regis College as a faculty, now Associate Professor. She has published 20 research and review articles in SCI journals.