The Impact of Infection and Inflamation in Oncologic FDG PET/CT


Assistant Professor of Radiology Tehran University of Medical Sciences



18F-FDG PET/CT is an integral part of modern-day practice, especially in the management of individuals presenting with malignant processes However, due to its detection of cellular metabolism, it is not truly tumor-specific.
Unexpected and incidental foci of uptake in oncologic 18F-FDG PET/CTs are relatively common  with  diagnostic  considerations including unusual sites of metastases, a second synchronous neoplasm, surgical or procedural interventions, as well as infection and inflammation. Given their increased uptake on 18F-FDG PET/CT, infectious and inflammatory responses have the potential to be misinterpreted as metastatic disease. This presentation aims to provide a pictorial review and analysis of cases that depict infective and inflammatory uptake as normal variants, pitfalls, and artifacts on 18F-FDG PET/CT oncologic imaging. The impact of this presentation is to help minimize poor imaging quality and erroneous interpretations and diminish misdiagnoses that may impact the adequate management of patients with undesirable consequences. We are going to learn about imaging features distinguishing infection and inflammation from malignancy regarding anatomical regions (head and neck, thorax, abdominopelvic) and also discuss the differential diagnosis of infection and inflammation process in each common cancer. Each topic has illustrative examples.
at the end of the session, the radiologist should be able to understand the Mechanism of uptake and metabolism of 18F-FDG in inflammation, infection, and tumor cells, as unusual and common incidental patterns of radiopharmaceutical uptake due to infectious and inflammatory etiologies to avoid misdiagnosis of malignancy. Differentiating inflammation and infection uptake from malignancy with the utilization of CT findings as well as patient history. additional diagnostic steps that need to be performed to confirm the etiology of abnormal patterns of FDG distribution.