Background: Phase I of the Australian Imaging, Biomarkers and Lifestyle (AIBL) Flagship Study of Ageing, a three-year prospective longitudinal study recruiting 1,112 volunteers from a cross-section of Australia's elderly population, concluded with more than a quarter of the participants undergoing PiB-PET scans. Methods: Two hundred and eighty-seven participants received PiB PET scans: 177 Healthy controls (HC); 57 Mild Cognitive Impairment (MCI) subjects; and 53 mild Alzheimer's disease (AD) patients. HC were further classified according to the presence or absence of an ApoE4 allele and by their subjective memory complaints (MC). All participants underwent a comprehensive neuropsychological examination, a MRI and a PiB-PET scan. Correlational analyses were performed between the different study outcomes. Results: Cortical PIB binding was markedly elevated in all AD patients except one. MCI subjects presented either an “AD-like” (63%) or normal pattern. Cortical PiB retention was abnormal in 34% of HC and its prevalence increased with age. HC with subjective memory complaints carrying an ApoE4 allele had significantly higher Aβ burdens than non ApoE4 carriers. Conclusions: Phase I of the AIBL study has established the foundations for the longitudinal assessment of Aβ burden in HC, MCI and AD. This will assist the development of techniques for early detection of AD while providing a cohort suitable for targeted early intervention studies.
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