Differential microstructural and morphological abnormalities in mild cognitive impairment and Alzheimer's disease: Evidence from cortical and deep gray matter |
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| Authors: | Nan‐Jie Gong Chun‐Chung Chan Lam‐Ming Leung Chun‐Sing Wong Russell Dibb Chunlei Liu |
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| Affiliation: | 1. Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California;2. Brain Imaging and Analysis Center, Duke University School of Medicine, Durham, North Carolina;3. Department of Geriatrics & Medicine, United Christian Hospital, Hong Kong, China;4. Department of Psychiatry, United Christian Hospital, Hong Kong, China;5. Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China;6. Center for In Vivo Microscopy, Duke University School of Medicine, Durham, North Carolina;7. Helen Wills Neuroscience Institute, University of California, Berkeley, California;8. Department of Radiology, Duke University School of Medicine, Durham, North Carolina |
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| Abstract: | One aim of this study is to use non‐Gaussian diffusion kurtosis imaging (DKI) for capturing microstructural abnormalities in gray matter of Alzheimer's disease (AD). The other aim is to compare DKI metrics against thickness of cortical gray matter and volume of deep gray matter, respectively. A cohort of 18 patients with AD, 18 patients with amnestic mild cognitive impairment (MCI), and 18 normal controls underwent morphological and DKI MR imaging. Images were investigated using regions‐of‐interest‐based analyses for deep gray matter and vertex‐wise analyses for cortical gray matter. In deep gray matter, more regions showed DKI parametric abnormalities than atrophies at the early MCI stage. Mean kurtosis (MK) exhibited the largest number of significant abnormalities among all DKI metrics. At the later AD stage, diffusional abnormalities were observed in fewer regions than atrophies. In cortical gray matter, abnormalities in thickness were mainly in the medial and lateral temporal lobes, which fit the locations of known early pathological changes. Microstructural abnormalities were predominantly in the parietal and even frontal lobes, which fit the locations of known late pathological changes. In conclusion, MK can complement conventional diffusion metrics for detecting microstructural changes, especially in deep gray matter. This study also provides evidence supporting the notion that microstructural changes predate morphological changes. Hum Brain Mapp 38:2495–2508, 2017. © 2017 Wiley Periodicals, Inc. |
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| Keywords: | Alzheimer's disease mild cognitive impairment diffusion kurtosis imaging diffusion tensor imaging gray matter volume cortical thickness microstructure |
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