Salivary Gland Uptake on 18 F‐Florbetaben PET Did Not Demonstrate Additional Diagnostic Value for Alzheimer's Disease

Abstract Objectives Saliva, like other body fluids, has been investigated as a source of biomarkers for Alzheimer's disease (AD) due to its accessibility. Recently, decreased amyloid‐PET uptake in the salivary glands of patients with AD was reported, prompting interest in the potential clinical relevance of that finding. This study evaluates the association between salivary gland uptake on 1 8 F‐florbetaben PET and cortical amyloid burden and assesses its diagnostic value. Methods We retrospectively analyzed 73 patients who underwent 18 F‐florbetaben PET imaging. Salivary gland uptake (SUVR SG ) was measured and compared with the cortical amyloid burden, severity of dementia, and clinical diagnoses (cognitively normal, mild cognitive impairment, and dementia). Diagnostic performance was assessed using receiver operating characteristic (ROC) curve analyses. Results The mean SUVR SG was 1.43 ± 0.29, with no significant differences based on the cortical amyloid burden, severity of dementia, or clinical diagnosis. SUVR SG did not correlate with the cortical amyloid burden (ρ = −0.103, p > 0.05). The area under the ROC curve and volume under the ROC surface indicated that SUVR SG had poor diagnostic performance. Conclusions Salivary gland uptake on 18 F‐florbetaben PET was not associated with the cortical amyloid burden or clinical stage of AD, and it did not demonstrate diagnostic value. Further research is needed to explore its biological significance and standardization methods.