Nuclear medicine imaging to guide antibiotic therapy: an expert review

Bacterial infections and multidrug resistance remain a major global threat. New clinical tools are, therefore, urgently needed to identify bacterial infections and monitor response to antibiotics. Nuclear medicine imaging affords unique opportunities to target and identify bacterial infections, enabling spatial characterization as well as noninvasive, temporal monitoring of the natural course of the disease and response to therapy. In this expert review, we present an overview of the role of [18F]-FDG PET/CT and WBC scintigraphy with or without SPECT/CT in predicting treatment response to antibiotics and guide their interruption. A decrease in the [18F]FDG uptake or a change of uptake patterns could be potentially used to assess the results of antibiotic therapy in patients with different infectious diseases, despite robust evidence lacking. Concerning WBC scan, their high specificity to target and accumulation over time in infected areas is crucial for the differential diagnosis between infections and sterile inflammation, thus being useful also for therapy follow-up. However, specificity can be reduced in patients with ongoing antibiotics and little is known about the best time window to perform scintigraphy. Finally, we analyzed the potential usefulness of most promising radiolabelled bacterial tracers as potential alternative to FDG and WBC for therapy follow-up.