F-18 FDG PET/CT as a valuable imaging tool for assessing treatment efficacy in inflammatory and infectious diseases.

Activated inflammatory cells like neutrophils, macrophages, and lymphocytes have increased F-18 FDG uptake, causing significant tracer accumulation in inflammatory and infectious processes. In this report, we have illustrated F-18 FDG PET/CT features related to systemic sarcoidosis, large-vessel arteritis, abdominal tuberculosis, and pleural aspergillosis in 4 selected patients, who underwent scintigraphic evaluation before and after anti-inflammatory or antibiotic treatment. The evolution of radiotracer uptake intensity reflected the efficacy of medical treatment, permitting either a better modulation of drug dosage or a radical modification of therapeutic strategy. Independently from the cost and access to this type of medical imaging, F-18 FDG PET/CT could have a potential role in assessing treatment efficacy in selected non-neoplastic conditions, allowing morphofunctional cartography of residual inflammatory localizations.