Advantages and limitations of 18-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography in the diagnosis of infective endocarditis

Abstract

Introduction: The early diagnosis of infective endocarditis (IE) is a medical challenge and a multidisciplinary approach is essential to improve its frequently fatal prognosis. Our goal was to evaluate the usefulness of [¹⁸F]2-fluoro-2-deoxy-d-glucose positron emission tomography (¹⁸F-FDG PET) in the diagnosis of this disease.

Materials and methods: We prospectively assessed 43 patients (five female and 38 male) with clinical suspicion of IE between 2014 and 2017. All patients underwent transesophageal echocardiography (TEE) and an ¹⁸F-FDG PET scan, and the results were compared. A positive PET finding was defined as increased FDG uptake on cardiac valves or intracardiac devices.

Results: Out of 43 patients with suspected IE, the diagnosis was confirmed in 30 cases (79.7%). ¹⁸F-FDG PET was positive in 24 patients, with 19 showing FDG uptake on cardiac valves (two native and 17 prosthetic) and five on cardiac devices, being concordant with echocardiographic findings in 11 cases. ¹⁸F-FDG PET sensitivity was 80%, specificity 92%, positive predictive value (PPV) 96% and negative predictive value (NPV) 66%. Echocardiography presented sensitivity, specificity, PPV and NPV of 36%, 84%, 84% and 36%, respectively.

Conclusions: ¹⁸F-FDG PET proved to be a sensitive technique with a high diagnostic value in patients with prosthetic valves and intracardiac devices and suspected IE. Its utility decreased dramatically in patients with suspected IE on native valves, in which TEE presented higher sensitivity and thus better diagnostic value.

Keywords: 18-Fluoro-2-deoxy-d-glucose; Ecocardiograma transesofágico (ETE); Endocardite infecciosa (EI); Infective endocarditis; Positron emission tomography; Tomografia por emissão de pósitrões (18F-FDG-PET); Transesophageal echocardiography.