FIGURE 4.

Complementarity of ⁶⁸Ga-FAPI-04 PET/CT and ^99mTc-MDP bone scan in imaging a 52-year-old woman with SAPHO syndrome. The woman presented with facial acne for 3 years and whole-body bone pain for 1 year. Laboratory examination showed elevated ESR (48 mm/h) and hs-CRP (11.63 mg/L). The maximum intensity projection (A) of ⁶⁸Ga-FAPI-04 PET/CT showed increased tracer uptake in the multiple bones and joints. Axial PET/CT (B–D) showed abnormal tracer uptake in the second cervical vertebra spinous process (dotted arrows), without apparent bone density changes. In contrast to PET/CT, ^99mTc-MDP bone scan additionally showed increased tracer uptake in the left sternoclavicular and sternocostal joints (E, long arrow), but not detected the lesions of the second cervical vertebra spinous process (F–H, dotted arrows) and the right sixth costal vertebra joint (curved arrow).