Diagnosis by (18)F-FDG PET/CT of infective endocarditis, staging and monitoring of antibiotic treatment after transposition of surgically corrected great arteries

Infective endocarditis is one of the leading causes of fever of unknown origin in those patients with intravascular catheters, prosthetic valves or cardiovascular implantable electronic devices. The diagnosis of infective endocarditis is made according to modified Duke criteria, which are based on blood culture and echocardiographic findings. Demonstration of vegetation with the transoesophageal echocardiography may be difficult in these cases with previous anatomical changes, especially in early phases. Positron emission tomography with (18)F-fluorodeoxyglucose ((18)F-FDG PET/CT) is well known to show an increased glucidic metabolism in malignant, inflammatory, and infectious processes. Thus, it provides useful functional imaging that enables the disease causing the fever of unknown origin to be detected well before structural changes are evident. Moreover, (18)F-FDG PET/CT helps to detect infectious extra-cardiac involvement, since the whole body is imaged with this technique. (18)F-FDG PET/CT may have an additional promising role for the monitoring of response to antimicrobial therapy in patients with established infective endocarditis, thus evaluating standard treatment outcome, as well as evaluating the need for alternative/intensified treatment options.