Alzheimer’s disease (AD) is the most common form of dementia accounting for 60% to 80% of total dementia cases and the sixth leading cause of death in the US. Over 25 million people are affected by the disease and as the aging population increases, this number is expected to double by 2050. Although disease modifying treatments for AD are now becoming available, they are not curative, and there remains a pressing need for additional therapeutic strategies. Disruption of brain glycolytic metabolism is recognized as a hallmark feature of AD that has deleterious consequences given the brain’s high metabolic rate. Ketone bodies are alternative substrates that can be used by the brain to support mitochondrial oxidate metabolism. Mounting evidence suggests that the AD brain may metabolize endogenous ketones derived from myelin lipids, leading to derangements in lipid homeostasis and demyelination. Ketogenic diets or ketone drinks are now being investigated as promising therapeutic strategies in the AD continuum to meet brain energy requirements and to maintain lipid homeostasis. However, a major challenge in the development, validation, and optimization of ketone therapies in AD is the lack of robust non-invasive tool to probe the metabolic fate of lipids and ketone bodies in the human brain. Our preliminary data demonstrate the feasibility of using deuterium magnetic resonance spectroscopy (DMRS) with deuterium labeled precursors to directly characterize and quantify ketone metabolism in the brain. In addition, nuclear Overhauser effect (NOE) based MRI offers the potential of measuring changes in myelin/lipid integrity with high sensitivity. We propose to further develop and optimize DMRS for tracking glucose and ketone metabolism and NOE MRI for studying brain lipids with a goal to probe initiating mechanisms underlying brain metabolic derangements in AD. Specifically, we will first establish the precision of the methods in measuring glucose and ketone metabolism and brain lipids in AD pathology. Then, we will perform longitudinal DMRS and NOE MRI in AD mouse models (APP-KI, AD-APP-KI) that closely recapitulate human AD to determine the onset and progression of changes in ketone and lipid metabolism and their association with the changes in immunohistochemical measures of myelin, lipids and other hallmark features of AD. Successful completion of the proposed project will lead to: (i) new mechanistic insights about the critical role of lipid catabolism and ketone metabolism in the initiating stages of AD onset and progression (ii) validated imaging biomarkers that can measure changes in ketone metabolism and lipid integrity in AD disease progression and its treatment with ketone supplementation, and (iii) noninvasive and clinically translatable biomarkers that can be used to identify and longitudinally evaluate disease targets and disease modifying ketone therapies, thereby contributing to enhanced patient care.