The relationship of 18F-FDG-PET to other common biomarkers of dementia in a clinical cohort with memory deficits

Background: Early biomarker-based diagnosis of Alzheimer's disease (AD) is essential, particularly with the increasing availability of new therapeutic options. However, the relationship between imaging and cerebrospinal fluid (CSF) biomarkers, especially in the context of F-18 Fluorine-fluorodeoxyglucose positron emission tomography (F-18-FDG-PET), remains insufficiently understood. Objective: The aim of this study was the evaluation of the relationship between F-18-FDG-PET and other common fluid and imaging AD-biomarkers in a clinical cohort of patients with cognitive decline and suspected AD. Methods: We included n = 90 patients with cognitive decline and clinically suspected AD that underwent F-18-FDG-PET imagining at our facility. Clinical and imaging data including patient characteristics, CSF biomarkers, Mini-Mental State Examination (MMSE), F-18-FDG-PET and F-18-Florbetaben-PET were retrospectively analyzed. PET images were quantified in several brain regions. Results: F-18-FDG uptake correlated with CSF amyloid-beta (A beta)40, A beta 42, and the A beta 42/40 ratio in several brain regions, but not with regional F-18-Florbetaben uptake. F-18-FDG uptake inversely correlated with t-tau and p-tau in CSF. Furthermore, a correlation between MMSE and F-18-FDG uptake was also detected in several brain regions. F-18-FDG-PET and its combination with CSF markers showed the highest predictive power for disease severity. Conclusions: The study highlights the potential of integrating F-18-FDG-PET with CSF biomarkers to improve the diagnosis, prognosis, and monitoring of AD, emphasizing the complexity and regional specificity of biomarker interactions in neurodegeneration.