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Updated: Aug 29, 2026
Ultrasonographic Evaluation of Salivary Glands for Sjogren's Syndrome: Diagnostic and Monitoring Insights
Published on: October 13, 2023
68Ga-FAPI PET/CT for assessing fibroblast activation and disease activity in primary Sjögren's disease: a prospective
Jiarou Wang1,2, Yimeng Jia3,4, Jialin Xiang1,2
1Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, State Key Laboratory of Complex Severe and Rare Diseases, Beijing, PR China.
Objective:
Sjögren's disease (SjD) is an autoimmune exocrinopathy characterized by chronic glandular inflammation. Fibroblast activation protein (FAP) is a promising imaging biomarker for local inflammation. This study aims to evaluate the utility of [68Ga]Ga-FAPI PET/CT in SjD, assess its correlation with disease activity, and explore its role in monitoring treatment response.
Methods:
This study enrolled SjD patients (2016 ACR-EULAR criteria), with cancer patients as controls. All SjD participants underwent EULAR Sjögren's Syndrome Patient Reported Index and EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI) assessments and serological testing; labial gland biopsies were additionally performed in a subset. The enrolled patients subsequently underwent longitudinal follow-up.
Results:
[68Ga]Ga-FAPI-04 PET/CT imaging revealed significantly higher tracer uptake in the lacrimal, parotid and sublingual glands of SjD patients compared with controls (all P < 0.001), while no significant difference was observed in the submandibular gland. Receiver operating characteristic analysis demonstrated high diagnostic performance, particularly for parotid gland parameters [maximum standardized uptake value (SUVmax): AUC = 0.89; 95% CI: 0.84-0.94; P < 0.001]. After correcting for multiple comparisons, parotid gland uptake remained significantly and positively correlated with ESR (r = 0.51-0.58, P < 0.05) and RF (r = 0.50-0.57, P < 0.05). Regarding disease activity, only parotid total lesion fibroblast (TLF) activation demonstrated a significant correlation with the ESSDAI score (r = 0.48, P < 0.05). Follow-up imaging in nine patients showed that glucocorticoid therapy was associated with concurrent reductions in clinical scores and salivary gland FAPI uptake.
Conclusion:
[68Ga]Ga-FAPI PET/CT noninvasively assesses fibroblast activation in SjD, correlates with disease activity and treatment response, and supports its potential clinical utility.
Trial Registration:
This study has been registered online at NIH ClinicalTrial.gov (NCT07062523).