Molecular PET Imaging in Alzheimer’s Disease

Abstract

Purpose: The complexities of pathological changes in Alzheimer’s disease (AD) and their relationships with associated risk factors and clinical symptoms, and the development of disease-modifying therapy or preventive intervention for AD are being intensively investigated. The emerging advances in brain positron emission tomography (PET) imaging allow for in vivo visualization and quantitation of specific neurochemical and molecular pathophysiologic changes in the brain tissue. This review is focused on the recent advances in molecular PET imaging of the brain and its clinical applications in AD. Methods: The development in PET radiopharmaceuticals targeting brain glucose metabolism, amyloid accumulation, tau protein aggregation, neuroinflammation, acetylcholine system, and synaptic density are discussed along with their potential clinical applications in AD. Results: PET imaging studies can provide diagnostic and prognostic biomarkers of AD, as well as for selection and monitoring of novel therapies. Given the complexity and potential overlapping pathologies and comorbidities, a single biomarker can neither provide the diagnostic certainty required for early detection of AD nor the identification of presymptomatic at-risk individuals. Therefore, multimodal studies are required to better understand the relationships between different biomarkers, answer the controversial issues, and incorporate new diagnostic criteria for the various stages in the continuum of AD. Conclusion: Molecular PET imaging studies have significant roles in the clinical practice and the clinical trials of novel therapeutic agents in AD. However, standardization and validation across multiple participating sites are still required for the subsequent transition from clinical research into clinical practice.