Imaging Infection and Inflammation with F-18 FDG-PET

N uclear medicine plays an important role in the evaluation of inflammation and infection. Radionuclide imaging is complementary to CT in the postoperative patient and is used to help differentiate postoperative changes from infection. In the case of painful joint replacement, radionuclide studies are the primary diagnostic imaging modality for differentiating infection from other causes of prosthetic failure. Several tracers are available for imaging infection: technetium-99m diphosphonates, gallium-67 citrate, indium-111and technetium99m-labeled leukocytes, and the recently approved antigranulocyte antibody Tc-99m fanolesomab. Although useful, each of these tracers has disadvantages, and investigators continue to seek alternative agents. Fluorine-18 FDG is readily available, exquisitely sensitive, and relatively inexpensive. PET imaging using F-18 FDG is rapidly completed, and the high-resolution tomographic images are superior to those provided by most SPECT agents. Thus, it is not surprising that the use of FDG-PET for detecting infection and inflammation has attracted interest.