Role of FDG PET/CT in infection and inflammation

Learning Objectives 1-Understand the mechanism of FDG uptake in infection/inflammatory processes 2-Gain an understanding of indications for FDG-PET 3-To demonstrate the advantages of FDG PET/CT in FUO over other conventional nuclear medicine imaging

FDG-PET imaging has been widely used for diagnosing, staging, and detecting the recurrence of many cancer . Also FDG rapidly accumulates at the sites of infection and inflammation with high target-background ratio. FDG has been approved by US Food and Drug Administration US FDA) and European Medicines Agency (EMEA) and authorized as a diagnostic radiopharmaceutical in the diagnosis of infection. The mechanism of FDG localization in infection is like in cancer that cells involved in infection and inflammation, especially neutrophils and the monocyte/macrophage, are able to express high levels of glucose transporters, especially GLUT1. The common indications of FDG PET/CT in infection and inflammation included the following in descending order of accuracy, Sarcoidosis, Osteomyelitis, Spondylodiskitis, Fever of Unknown Origin, vasculitis, diabetic foot, prosthesis (especially hip), Vascular grafts. Also it used for assess extent of fungal infection and evaluation of therapy in infectious or inflammatory diseases. The advantages of FDG PET/CT are that no need for time consuming and hazards manipulation of blood for labeling in WBC imaging, no need for complementary bone or bone marrow scan, can detect a tumor or infection focus as a cause of FUO, anatomical localization and better resolution. However, over the past 20 years the value of WBC/MoAb imaging in different infectious diseases has been well established and larger prospective studies assessing the role of FDG-PET/CT in management of patients with infectious diseases and established interpretation criteria are needed. We will presented some cases of infection and inflammation imaging by FDG PET/CT.