The diagnosis of infectious endocarditis is not always easy and is based on several clinical and imaging arguments. Positron Emission Tomography - Computed Tomography (PET-CT) has been validated for endocarditis on prosthetic valves but few studies concern the native valves. The purpose of the study is to estimate the diagnostic sensitivity of [18F]-fluoro-2-deoxyglucose (18F-FDG) PET-CT in patients with endocarditis on native valves according to the European Society of Cardiology 2015 (ESC 2015) modified diagnostic criteria of infective endocarditis classified as definite at three months of follow-up (baseline test).

Infectious endocarditis remains a serious pathology with an intra-hospital mortality of between 15 and 30%. The prognosis of patients depends on the speed of diagnosis and the beginning of the appropriate treatment.

Currently, the diagnosis of endocarditis is based on the ESC 2015 modified criteria. Echocardiography techniques play a key role, but can be negative in 20% of endocarditis. 18F-FDG PET-CT showed promising results in the management of prosthetic valve endocarditis and / or stimulation material.

However, few studies have been carried out on the contribution of PET-CT in the diagnosis of endocarditis on native valves, with discordant results. But this is the majority of endocarditis (70% of cases).

A 18F-FDG PET-CT will be performed in all patients included in the study in addition to standard care for endocarditis, within 5 days of the beginning of their management in the university hospital center of Bordeaux after verification of inclusion and exclusion criteria and signature of consent.

The included patients will be reviewed at Month 3 during a consultation with the completion of a clinical examination, an electrocardiogram, a biological assessment and a transthoracic ultrasound.

Adverse events and serious adverse events will be collected throughout the study.

Inclusion Criteria:

• Any patient ≥ 18 years treated at the university hospital center of Bordeaux for suspicion of infectious endocarditis on a native valve with a "definite" or "possible" diagnosis according to the ESC 2015 modified diagnostic criteria, agreeing to participate,
• Affiliated person or beneficiary of a social security scheme,
• Free, informed and written consent (no later than the day of inclusion and before any exam required by the research).

Exclusion Criteria:

• Patient with a vital failure (haemodynamic, respiratory or neurological instability), requiring treatment in the intensive care unit and / or urgent surgery incompatible with performing PET-CT,
• Pregnant or nursing woman,
• Patient who has already been treated for infective endocarditis within six months of enrollment,
• Patient who had cardiac surgery in the two months preceding inclusion,
• Patient who has previously been hypersensitive to fluorodeoxyglucose and / or excipients of the radiotracer,
• Patient unable to sign consent,
• Patient under legal protection,
• Women of childbearing age who do not benefit from effective contraception (HAS criteria),
• Patient in a period of relative exclusion from another research protocol.

The interpretation of the PET-CT will be performed by a nuclear medicine expert who is expert in cardiac imaging and infectious pathology, blinded to other imaging tests.