Investigating Regional Relationships between Amyloid-Beta and Brain Metabolism in Healthy Elderly Controls

Introduction: Deposition of amyloid-β (Aβ) in the brain is a hallmark of Alzheimer's disease (AD), but its consequences regarding brain metabolism are largely unknown. Regional Aβ accumulation can be assessed with Pittsburgh compound-B positron-emission-tomography (PiB-PET) and magnetic resonance spectroscopic imaging (MRSI) non-invasively quantifies regional brain metabolite levels. This study aims to investigate potential regional effects of Aβ accumulation on brain metabolite levels in healthy controls and will be extended to clinical cohorts with mild cognitive impairment and AD. Methods: MRSI was performed at high field strength of 7 Tesla to increase signal-to-noise ratio and spatial resolution, and was applied to a pilot-cohort of healthy, cognitively normal elderly adults (n=14). Individual cortical Aβ load was quantified based on PiB-PET late frame signals. Regional correlation of PiB-PET signals with the respective metabolite-levels of MRSI was performed based on tissue-specific probability maps. Results: As this is an on-going study, recruitment of clinical cohorts will continue. The newest results regarding the relationship of individual cortical Aβ load with regional metabolite concentrations will be presented. Conclusion: Investigating the regional association between deposition of Aβ and corresponding brain metabolite levels will allow us to draw conclusions about regional Aβ-associated neuronal stress. This study will characterize the metabolic signature of asymptomatic brain amyloidosis, and will help to evaluate MRSI as a potential AD biomarker