In:
Alzheimer's & Dementia, Wiley, Vol. 18, No. S5 ( 2022-12)
Abstract:
Diffusion tensor imaging (DTI) has been commonly used to characterize microstructural changes associated with aging and Alzheimer’s disease (AD) dementia. However, DTI ignores non‐Gaussian diffusion, which limits its ability to describe the more restricted diffusion present within cellular structures. Neurite Orientation Dispersion and Density Imaging (NODDI) and Mean Apparent Propagator (MAP) MRI are two alternative diffusion MRI (DWI) models which can be used to calculate parameters that better characterize alterations observed in tissue microstructure. To investigate the sensitivity of DTI, NODDI, and MAP to white matter changes associated with aging and dementia, we examined the relationship between 15 DWI parameters, age, and AD clinical status in 418 aging adults along the AD continuum. Methods 418 participants (328 cognitively unimpaired [CU], 60 Mild Cognitive Impairment [MCI] , 30 AD) from the Wisconsin Registry for Alzheimer’s Prevention and the Wisconsin Alzheimer’s Disease Research Center were imaged with multi‐shell DWI (Table 1). 15 DWI parameters were extracted from the cingulum, including 4 DTI (FA, MD, RD, AxD), 3 NODDI (ODI, NDI, ISO) and 8 MAP (RTOP, RTAP, RTPP, MSD, QIV, NG, NG || , NG ⊥ ) metrics. All measures were fit to the following linear model: Diffusion Metric = β 0 +β 1 * (age)+ β 2 * (sex)+β 3 * (status)+β4 * (age * status)+Ε Results DWI age trajectories and model parameters are provided in Figures 1‐2 and Tables 2‐4, respectively. 12 of 15 DWI metrics were significantly associated with age, including all 8 MAP measures. Additionally, 6 metrics were associated with AD and 8 were associated with MCI. The interaction between age and AD was significant for RTOP, NDI, FA, and AxD, while the interaction between age and MCI was significant for RTOP, RTPP, MSD, NG, NG ⊥ , ISO, MD, RD, and AxD (P corr = 0.05). Conclusion The significant effects of clinical status and interactions between age and clinical status, may indicate that these metrics are sensitive to microstructural alterations specific to dementia. Furthermore, the meaningful interactions between age and MCI in 5 of 8 MAP parameters suggests that MAP MRI may be particularly useful for detecting early WM degeneration along the AD continuum. Future work will translate this analysis to larger cohorts and assess MAP parameters in gray matter.
Type of Medium:
Online Resource
ISSN:
1552-5260
,
1552-5279
Language:
English
Publisher:
Wiley
Publication Date:
2022
detail.hit.zdb_id:
2201940-6
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