Comparison of 68Ga-DOTA-FAPI-04 and 18F-FDG PET/CT in Patients With SAPHO Syndrome

68Ga-DOTA-FAPI-04 PET/CT was performed on a cohort of 21 patients with known SAPHO syndrome. All patients underwent 68Ga-DOTA-FAPI-04 and 18F-FDG PET/CT on 2 consecutive days. The positive rates of the PET/CT scans at the sites of the osteoarticular symptom, the uptake values, and agreement with clinical osteoarticular symptom were compared.A total of 38 sites of involvement were detected. 18F-FDG PET/CT revealed 28 lesions. In contrast, 68Ga-DOTA-FAPI-04 PET/CT detected not only all lesions shown on 18F-FDG PET/CT but additional 10 lesions. 68Ga-DOTA-FAPI-04 scan also demonstrated significantly higher uptake and target-to-background ratio than 18F-FDG studies in the skeletal involvements. The agreement between 68Ga-DOTA-FAPI-04-positive lesions and current osteoarticular lesions was substantial (κ = 0.79, P < 0.001), whereas 18F-FDG had low to moderate agreement with clinical symptoms (κ = 0.52, P < 0.001).68Ga-DOTA-FAPI-04 has potential as a promising imaging agent for the evaluation of SAPHO syndrome.