Multilevel Deficiency of White Matter Connectivity Networks in Alzheimer’s Disease: A Diffusion MRI Study with DTI and HARDI Models

Alzheimer’s disease (AD) is the most common form of dementia in elderly people. It is an irreversible and progressive brain disease. In this paper, we utilized diffusion-weighted imaging (DWI) to detect abnormal topological organization of white matter (WM) structural networks. We compared the differences between WM connectivity characteristics at global, regional, and local levels in 26 patients with probable AD and 16 normal control (NC) elderly subjects, using connectivity networks constructed with the diffusion tensor imaging (DTI) model and the high angular resolution diffusion imaging (HARDI) model, respectively. At the global level, we found that the WM structural networks of both AD and NC groups had a small-world topology; however, the AD group showed a significant decrease in both global and local efficiency, but an increase in clustering coefficient and the average shortest path length. We further found that the AD patients had significantly decreased nodal efficiency at the regional level, as well as weaker connections in multiple local cortical and subcortical regions, such as precuneus, temporal lobe, hippocampus, and thalamus. The HARDI model was found to be more advantageous than the DTI model, as it was more sensitive to the deficiencies in AD at all of the three levels.

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P3-264: Using White Matter Seed Regions Produces Stronger and More Complex Structural Networks in Healthy Elderly Subjects and Subjects with Alzheimer’S Disease

Alzheimer s & Dementia ◽

10.1016/j.jalz.2016.06.1927 ◽

2016 ◽

Vol 12 ◽

pp. P933-P933

Author(s):

Lauren Zajac ◽

Bang-Bon Koo ◽

Ronald Killiany

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

White Matter ◽

Elderly Subjects ◽

Healthy Elderly ◽

Complex Structural ◽

Structural Networks ◽

Healthy Elderly Subjects

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Application of diffusion tensor imaging in Alzheimer’s disease: quantification of white matter microstructural changes

Egyptian Journal of Radiology and Nuclear Medicine ◽

10.1186/s43055-021-00460-x ◽

2021 ◽

Vol 52 (1) ◽

Author(s):

Shereen Magdy Abdel Malak Esrael ◽

Ahmed Mostafa Mohamed Hamed ◽

Eman M. Khedr ◽

Radwa Kamel Soliman

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Diffusion Tensor Imaging ◽

White Matter ◽

Healthy Subjects ◽

Diffusion Tensor ◽

Mean Diffusivity ◽

Elderly Subjects ◽

Potential Biomarker ◽

The Right

Abstract Background Alzheimer’s disease (AD) is the most common cause of dementia in the aging population, responsible for 60–70% of all demented cases. Diffusion tensor imaging (DTI) is a very recent technique that allows the mapping of white matter (WM) microstructure changes in neurological disorders. The current study was conducted to compare DTI parameters between AD patients and healthy elderly subjects and to determine whether DTI can act as a potential biomarker for AD. Results There were significant differences in Modified Mini-Mental State Examination (MMMSE) and Clinical Dementia Rating (CDR) between the two groups. As regards the DTI parameters, significant differences were found between AD patients versus healthy subjects, in the mean diffusivity (MD) of the splenium [(1.05 ± 0.19) vs. (0.92 ± 0.22) , P=0.03], the MD of the right uncinate fasciculus [(0.92 ± 0.04) vs. (0.87 ± 0.05), P= 0.01], and MD of the right arcuate fasciculus (AF) [(0.83 ± 0.04) vs. (0.79 ± 0.04) P =0.01], as well as the MD of the right and left inferior fronto-occipital fasiculus (IFOF) [(0.89 ± 0.06) vs. (0.83 ± 0.04), P=0.01]. In addition, there were significant differences in the fractional anisotropy (FA) of the right and left cingulum between both groups [(0.45 ± 0.02) vs. (0.47 ± 0.03), P=0.01 and (0.45 ± 0.03) vs. 0.49± 0.04), P=0.01, respectively]. The overall accuracy of the aforementioned parameters ranged between 73 and 81% with the MD of the left cingulum revealing the highest accuracy. Conclusion DTI proofed to be a useful tool in differentiating AD patients from healthy subjects. In our study, we found that the splenium, cingulum, IFOF, and the right UF and right AF are the main tracts involved in AD. The left cingulum provided the highest accuracy in differentiating AD from normal subjects.

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