Prospective Comparison of the Imaging Value of (99m)Tc-MDP Bone Scan and (68)Ga-FAPI-04 PET/CT in Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis Syndrome

This study aimed to explore the imaging value of (68)Ga-FAPI-04 PET/CT in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome and compare it with that of (99m)Tc-MDP bone scan. METHODS: Nineteen participants with SAPHO syndrome underwent (68)Ga-FAPI-04 PET/CT and (99m)Tc-MDP bone scan. Demographic data and clinical features were recorded, SAPHO imaging features were analyzed, and the osteoarticular lesion detection rate in both methods was calculated. RESULTS: This prospective study recruited 4 men and 15 women aged 52.4 ± 8.6 years. The anterior chest wall was involved in all participants (100%). Palmoplantar pustulosis was the most common (36.8%) skin symptom. (99m)Tc-MDP bone scan and (68)Ga-FAPI-04 PET/CT together detected 84 osteoarticular lesions, of which 91.7% (77/84) were detected by the former and 96.4% (81/84) by the latter. Furthermore, (68)Ga-FAPI-04 PET/CT detected 5 cases of knee and hip joint synovitis. CONCLUSIONS: (68)Ga-FAPI-04 PET/CT was more sensitive than (99m)Tc-MDP bone scan when evaluating osteoarticular lesions in SAPHO syndrome and could also evaluate synovial lesions. (68)Ga-FAPI-04 PET/CT could be a good imaging method for SAPHO syndrome but requires further verification in a more extensive research cohort.