Resolution of Pulmonary FDG-embolus on Same-day Delayed Imaging

A 32-year-old woman presented for an 18 F-FDG PET/CT scan for a lung nodule, which demonstrated background uptake. Incidentally, there was a focus of moderate-to-intense uptake in the right lung with no CT correlate. Repeat imaging 55 minutes later demonstrated resolution of this uptake, confirming a diagnosis of iatrogenic FDG-embolus, or "hot-clot" artifact. Most reported cases perform repeat radiotracer injection and imaging in the following days to confirm this artifact. This case illustrates that FDG-emboli can resolve on delayed imaging within an hour, and if so, repeat acquisition with a separate injection may be avoided, lowering radiation exposure for the patient.