Negative 18F-FDG and Positive 68Ga-FAPI-04 Findings in a Patient With Acute Exacerbation of Chronic Cholecystitis

Acute cholecystitis typically exhibits intense FDG uptake of the gallbladder wall. Radiolabeled fibroblast activation protein inhibitor (FAPI) is considered as a potential alternative agent for tumor-specific imaging. We report 18 F-FDG and 68 Ga-FAPI-04 PET/MR findings in a 44-year-old woman with acute exacerbation of chronic cholecystitis. The lesions show negative 18 F-FDG uptake but intense 68 Ga-FAPI-04 uptake in PET/MR. This case highlights the imperative for nuclear medicine clinicians to exercise vigilance when evaluating gallbladder lesions exhibiting intense 68 Ga-FAPI-04 but negative 18 F-FDG uptake.