The ¹⁸F-FDG–Positron Emission Tomography/Computed Tomography Examination

Abstract

The ¹⁸F-FDG–PET/CT scan is a recently introduced imaging technique that has rapidly become well established, particularly in the diagnosis of malignant disease. ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) is a radiolabeled structural analogue of 2-deoxyglucose and therefore serves as a tracer of glucose metabolism. It strongly accumulates in the brain, especially in the cortex and basal ganglia, whereas cardiac uptake is variable, frequently patchy. The accumulation of ¹⁸F-FDG activity in urine can interfere with the visualization of pelvic and, in some cases, abdominal abnormalities. Smooth muscle peristalsis results in circumscribed or diffuse gastrointestinal uptake. In the reticuloendothelial system and especially in the bone marrow, ¹⁸F-FDG uptake is highly variable as glucose accumulates in inflammatory as well as in tumoral cells. In adults, the ¹⁸F-FDG–PET/CT exam has been used increasingly for the staging and restaging of neoplasms such as lymphoma, head and neck carcinoma, colon cancer, and lung cancer, and in the localization of abdominal or pelvic abscesses and bone–joint and soft tissue infections, including infected joint prostheses, vasculitis, and tuberculosis. In the pediatric population, a small range of pathologies have been studied by means of ¹⁸F-FDG–PET/CT, including sarcomas, blastomas, lymphomas, and cerebral tumors.