PET/CT Imaging of Infectious Diseases: Overview of Novel Radiopharmaceuticals

Abstract

Infectious diseases represent one of the most common causes of hospital admission worldwide. The diagnostic work-up requires a complex clinical approach, including laboratory data, CT and MRI, other imaging tools, and microbiologic cultures. PET/CT with 18F-FDG can support the clinical diagnosis, allowing visualization of increased glucose metabolism in activated macrophages and monocytes; this tracer presents limits in differentiating between aseptic inflammation and infection. Novel PET radiopharmaceuticals have been developed to overcome these limits; 11C/18F-labeled bacterial agents, several 68Ga-labeled molecules, and white blood cells labeled with 18F-FDG are emerging PET tracers under study, showing interesting preliminary results. The best choice among these tracers can be unclear. This overview aims to discuss the most common diagnostic applications of 18F-FDG PET/CT in infectious diseases and, as a counterpoint, to describe and debate the advantages and peculiarities of the latest PET radiopharmaceuticals in the field of infectious diseases, which will probably improve the diagnosis and prognostic stratification of patients with active infectious diseases.

Keywords

• PET/CT
• ⁶⁸Ga-citrate
• ¹⁸F-FDG
• PET/MRI
• infection
• inflammation