Effectiveness of Contrast Agents and Molecular Indicators in Alzheimer's Diagnosis Through Pet and Spect Imaging on Animal Models: A Systematic Scoping Review Publisher



Abaszadeh Y¹ ; Ardalani R^{2, 3} ; Abadi ADN⁴ Show Affiliations
Source: Frontiers in Biomedical Technologies Published:2025

Abstract

Purpose: The importance of cognitive decline has increased due to population aging and lifestyle changes. A definitive diagnosis of Alzheimer's Disease (AD) is made only by postmortem histopathological examination, but in vivo imaging advances this diagnosis. The disease is associated with neuropathological features such as amyloid β (Aβ) plaques and Neurofibrillary Tangles (NFT) in the brain. The usefulness of contrast agents and compounds, such as SPECT and PET imaging, for the early identification of AD is investigated in this systematic scoping review. SPECT has been studied because it can yield reliable findings quickly, detect traces in data, and can link and evaluate the metabolism of mud and PET at high spatial resolution. The efficiency of molecular markers like tau protein, Translocator Protein (TSPO), and Amyloid β (Aβ), as well as contrast agents like [18F] fluorodeoxyglucose and [11C] acetate. Early detection and diagnosis of AD is very important, but current research on the effectiveness of contrast agents and molecules is limited. To address this gap, we conducted a systematic scoping review on PET and SPECT imaging to evaluate the role of these factors and indicators in the diagnosis of this disorder. Materials and Methods: A systematic search was conducted on August 30, 2023, in PubMed, using the PRISMA guidelines, without any time or language restrictions. The search was limited to PubMed because it is a comprehensive and extensive database in the medical sciences and the number of results we found there was sufficient. Three independent reviewers screened the studies based on criteria, and relevant data from the included articles were extracted and analyzed. Results: As a result of the initial search, 172 original articles were included in the study. Finally, data from 116 studies were extracted. The most used contrast agents were [18F] fluorodeoxyglucose and its derivatives, [11C] acetate, and chemicals based on iodine, respectively. The most often employed transgenic mouse strains in the studies were APP/PS1 and 5XFAD. On average, 23 animals were used in each study. Respectively, Amyloid beta, Tau protein, Translocator Protein (TSPO), Acetylcholinesterase (AChE), Monoamine Oxidase B (MAO-B), and Gonadotropin-Releasing Hormone Receptor (GnRHR) were identified the most as biomarkers in studies. Conclusion: The study on PET and SPECT imaging for diagnosing AD has limitations, including the use of animal models and not evaluating the long-term effects or safety of contrast agents. Further research is needed to confirm these findings in clinical settings and assess the long-term impact of these contrast chemicals. Copyright © 2025 Tehran University of Medical Sciences.