⁶⁸Ga-FAPI PET/CT features of thoracic sarcoidosis: a prospective observational study

Area of Science:

• Nuclear medicine
• Radiopharmacology
• Oncologic imaging

Background:

• Sarcoidosis is a multisystem granulomatous disease primarily affecting the lungs.
• 18F-FDG PET/CT is a sensitive tool for sarcoidosis assessment but requires fasting.
• The utility of 68Ga-FAPI PET/CT in sarcoidosis remains to be fully explored.

Purpose of the Study:

• To investigate the effectiveness of 68Ga-FAPI PET/CT in evaluating sarcoidosis.
• To analyze lesion uptake patterns and intensity with 68Ga-FAPI PET/CT.
• To correlate imaging findings with disease activity and treatment response.

Main Methods:

• Prospective observational study of 8 newly diagnosed thoracic sarcoidosis patients using 68Ga-FAPI PET/CT.
• Retrospective analysis of 16 sarcoidosis patients' 18F-FDG PET/CT scans.
• Calculation of SUVmax, SUVmean, and LBR for both imaging modalities.

Main Results:

• 68Ga-FAPI PET/CT detected FAPI-avid lesions in all patients, including lymph nodes and pulmonary infiltrates.
• Follow-up scans showed lesion shrinkage and decreased uptake after treatment, though some pulmonary lesions had minimal changes.
• Lymph node uptake parameters for 68Ga-FAPI tended to be lower than for 18F-FDG.

Conclusions:

• 68Ga-FAPI PET/CT is valuable for evaluating active and chronic granulomatous inflammation in sarcoidosis.
• This modality can aid in determining disease extent, detecting occult disease, and monitoring treatment.
• 68Ga-FAPI PET/CT shows potential for sarcoidosis management and may offer advantages over 18F-FDG PET/CT.