The value of FDG-PET/CT in the diagnostic work-up of extra cardiac infectious manifestations in infectious endocarditis

Infectious endocarditis (IE) is a serious condition with a high morbidity and mortality. The optimal management of IE depends not only on correct antibiotic therapy and surgery when needed, but involves identification of the portal of entry and detection of extracardiac infectious manifestations. To discover the latter an (18)F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET)/CT examination has been proposed. However, the diagnostic value of a PET/CT in this setting remains unresolved. Thus, we wished to assess the usefulness of a PET/CT study in patients with IE as a supplemental method to standard work-up in evaluating primary and distant infective foci. A retrospective cohort study of 72 IE patients admitted from 2008 to 2010, which had an ¹⁸F-FDG-PET/CT performed. Findings were assessed in relation to the routine work-up, which served as the “gold standard”. One hundred-fifty-nine infectious lesions were identified. ¹⁸F-FDG-PET identified 64 of these, and suggested another 50. Overall sensitivity and positive predictive value was 40 and 56 %, respectively, in detecting both cardiac and extracardiac infective foci. When excluding lungs and organs with high physiological FDG-uptake/secretion, the corresponding values increased to 87 and 52 %, respectively. ¹⁸F-FDG-PET/CT may be an important diagnostic tool in detecting extra cardiac infections in patients with IE, particularly in organs with low physiological glucose uptake.