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IC‐P‐148: Age‐related microstructural alterations in deep gray matter: In vivo evidence from diffusional kurtosis imaging
- Source :
- Alzheimer's & Dementia. 9
- Publication Year :
- 2013
- Publisher :
- Wiley, 2013.
-
Abstract
- [1] to compare 46 AD patients with 94 age-matched healthy volunteers (Australian Imaging Biomarkers & Lifestyle study). AFD is proportional to the image intensity, which is related to the quantity of intra-axonal water, and is therefore sensitive to the number of axons within a voxel (density). To perform voxel-wise comparisons of AFD, images were non-linearly warped to a common template image. We incorporated morphology information by modulating the AFD in each voxel based on the change to a fibre bundle’s cross-sectional area (atrophy). Modulation ensures the AFD in template space encapsulates both sources of axonal loss (axon density as measured by the MRI signal, and volume loss due to atrophy). We investigated whole-brain group AFD differences with and without modulation using novel tractography-based statistics. Results: Significant AFD decreases in AD were observed in white matter bundles known to be involved in language and memory (Fig.1). As shown in columns 1 & 2, the group AFD difference is more extensive when morphology information is included via AFDmodulation. Since AFD differences are associated with a voxel and direction (shown by the direction-colour-encoded tractogram in Fig.1) population differences can be attributed to a specific fibre bundle in regions with crossing-fibres (e.g. Arcuate Fasciculus).The absence of differences in fibre density (column 1) within regions previously detected using FA suggests that FA decreases detected in AD are largely caused by atrophy-induced partial volume changes. Conclusions: By incorporating morphology information, AFD is potentially a more sensitive and interpretable biomarker of axon degeneration compared to existing diffusion MRI measures based on image intensity alone.[1] Raffelt et al.2012,59(4):3976-94.
- Subjects :
- education.field_of_study
Epidemiology
Chemistry
Health Policy
Population
Partial volume
medicine.disease
computer.software_genre
White matter
Psychiatry and Mental health
Cellular and Molecular Neuroscience
medicine.anatomical_structure
Nuclear magnetic resonance
Atrophy
Developmental Neuroscience
Voxel
medicine
Arcuate fasciculus
Neurology (clinical)
Geriatrics and Gerontology
education
computer
Diffusion MRI
Tractography
Subjects
Details
- ISSN :
- 15525279 and 15525260
- Volume :
- 9
- Database :
- OpenAIRE
- Journal :
- Alzheimer's & Dementia
- Accession number :
- edsair.doi...........e6f7572697bf16f12aef0d7363851788