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

## TL;DR

This study found that amyloid-PET uptake in salivary glands does not help diagnose Alzheimer's disease or reflect disease severity.

## Contribution

The study shows that salivary gland uptake on 18F-florbetaben PET lacks diagnostic value for Alzheimer's disease.

## Key findings

- Salivary gland uptake did not correlate with cortical amyloid burden.
- No significant differences in uptake were found across cognitive stages.
- Diagnostic performance of salivary gland uptake was poor.

## Abstract

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
8F‐florbetaben PET and cortical amyloid burden and assesses its diagnostic value.

We retrospectively analyzed 73 patients who underwent 18F‐florbetaben PET imaging. Salivary gland uptake (SUVRSG) 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.

The mean SUVRSG was 1.43 ± 0.29, with no significant differences based on the cortical amyloid burden, severity of dementia, or clinical diagnosis. SUVRSG 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 SUVRSG had poor diagnostic performance.

Salivary gland uptake on 18F‐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.

Salivary gland uptake on 1
8F‐florbetaben PET was not associated with cortical amyloid burden in patients across the cognitive spectrum. No significant differences in salivary gland amyloid‐PET uptake were observed according to dementia severity or clinical diagnosis. These findings suggest that salivary gland amyloid‐PET uptake has limited clinical utility for assessing Alzheimer's disease.