The Amyloid Imaging to Prevent Alzheimer’s Disease Prognostic and Natural History Study (AMYPAD-PNHS) multimodal magnetic resonance imaging (MRI) dataset provides open-access longitudinal MRI data of 2759 cognitively normal or mild cognitive impairment individuals, encompassing (micro-)structural, physiological, and functional MRI sequences from 10 European parent cohorts. Processed and raw images, and image-derived (endo-)phenotypes, are organized in Brain Imaging Data Structure (BIDS) standards and accessible upon request, to enhance generalizability and comparability between future neuroimaging studies. This dataset supports preclinical Alzheimer’s disease (AD) and aging-related research by enabling robust multimodal analyses of neurodegeneration, microvascular pathology, and structural and functional connectivity changes, facilitating advanced investigations into preclinical AD mechanisms, informing early intervention strategies and allowing reproducible and centralized neuroimaging (endo-)phenotyping.
L. Pieperhoff, M. Tranfa, Prithvi Arunachalam et al.· Scientific Data· 0 citations
BACKGROUND: Quantitative amyloid-beta (A{beta})-PET is increasingly used in AD prevention trials. Although the Centiloid (CL) framework provides a common scale, variability persists across processing pipelines, including differences in template/native space, partial volume correction (PVC), and reference region. These choices may influence cut-points, and in turn positivity rates, as well as longitudinal accumulation rates. We examined cut-point estimates and inter-pipeline discordance in a community cohort where many are expected to have early A{beta} deposition. METHODS: We analysed [18F]florbetapir PET/MR data from predominantly cognitively unimpaired (~95%) individuals aged ~71 years at baseline (n=433) and at follow-up (n=328; ~2.4-year interval) in Insight 46 (1946 British birth cohort). Centiloids were derived using the standard pipeline and ten in-house pipelines employing alternative reference regions and PVC in native space. Gaussian mixture modelling estimated cut-points with bootstrapped uncertainty. We assessed A{beta}-discordance across pipelines as a function of standard CLs and examined follow-up CSF A{beta}42/A{beta}40 (n=120) and PET in individuals with discordant baseline classifications. RESULTS: Baseline cut-points were 10-23 CL across pipelines, classifying 16-25% as A{beta}-positive. Reliable accumulation cut-points were 3.5-6 CL/year, identifying 16-22% as accumulators. Uncertainty varied across pipelines. At baseline, 18% were discordant across PET measures, predominantly between 11-35 standard CLs. The discordant group showed higher A{beta}-PET accumulation and lower CSF A{beta}42/A{beta}40 than concordant negatives. CONCLUSIONS: Disagreement between A{beta}-PET methods was highest between 11-35 standard Centiloids and was frequently associated with accumulating A{beta}. These findings highlight the importance of considering cut-point uncertainty and methodological influences when interpreting early-stage amyloidosis.
W. Coath, A. Bollack, C. Scott et al.· medRxiv· 0 citations
A double-cutoff analysis suggest that scans in the 11 to 26 Centiloid range should be interpreted with caution depending on the context of use, and positivity cutoffs converged around 18 Centiloids (data-driven) and 27 Centiloids (visual reads).
G. Blazhenets, D. Soleimani-Meigooni, Konstantinos Chiotis et al.· Journal of the American Medi...· 5 citations
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