Relationship between regional atrophy and amyloid‐β load in Alzheimer's disease and mild cognitive impairment: Neuroimaging / multi‐modal comparisons. (7th December 2020)

• Record Type: Journal Article
• Authors: Bao, Yiwen; Cheung, Eva YW; Chau, Anson CM; Zhang, Huiqin; Zhang, H; Chiu, Patrick Ka‐Chun; Shea, Yat Fung; Kwan, Joseph SK; Mak, Henry
• Is Part Of: Alzheimer's & dementia. Volume 16(2020)Supplement 4
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-07
• Subjects: Alzheimer's disease -- Periodicals; Alzheimer Disease -- Periodicals; Dementia -- Periodicals; Démence; Maladie d'Alzheimer; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); 616.83
• DOI: 10.1002/alz.038686
• Languages: English
• ISSNs: 1552-5260

Abstract

Abstract: Background: Mild cognitive impairment (MCI) is a transition stage between cognitively unimpaired and Alzheimer's Disease (AD). Accumulation of amyloid‐β (Aβ) is considered as upstream event in the development of AD, while grey matter (GM) atrophy occurs in the late stage (Jack et al., 2010). In the cognitive continuum from MCI to AD, the correlation between two biomarkers are still not clearly known. From neuropathological perspective, the regional relationship between Aβ and GM atrophy is deficient. Method: Aβ deposition was assessed by 18F‐Flutemetamol‐positron emission tomography (PET) and magnetic resonance imaging (MRI) was used to estimate grey matter volume (GMV). 17 AD subjects and 28 MCI subjects were recruited in our study and underwent both MRI and PET scanning. Based on fused MRI and PET images, Statistical parametric mapping (SPM) and voxel‐based morphometry (VBM) were used to obtain 18F‐Flutemetamol Standardized uptake value ratio (SUVR) and GMV respectively in 8 paired standardized region‐of‐interests and at global level. The correlations were assessed by partial correlation test controlling for age and sex. Result: The mean differences of Aβ‐SUVR between AD and MCI were significant (p<0.0001) in most region‐of‐interests (ROIs) and globally. Compared to MCI group, AD group had significantly smaller GMV in hippocampus and mesial temporal lobe (p<0.0001) as well as globally(p<0.01) and in lateral temporal lobe (p<0.05). In AD group, GMV was negatively correlated with Aβ burden in left sensorimotor region (r=‐0.617, p<0.05), while positively correlated in mesial temporal lobe (left: r=0.682, p<0.0; right: r=0.522, p<0.05) and left hippocampus (r=0.548, p<0.05). For MCI group, GMV was negatively correlated with Aβ burden in right precuneus/posterior cingulate only (r=‐0.481, p<0.05). Conclusion: Our result indicates that the relationship of amyloid deposition and neurodegeneration might vary during the cognitive continuum. In MCI stage, Aβ burden may lead to severe atrophy in right precuneus/posterior cingulate, early site where Aβ deposition occurs. However, in AD stage, Aβ accumulation might lead to sensorimotor (left) atrophy and compensatory increase in GMV in mesial temporal lobe sites and left hippocampus where Aβ builds up relatively late.