The diagnostic value of 18F-FDG PET/CT in suspected native valve endocarditis - a terciary center experience

Background Infective endocarditis (IE) is difficult to diagnose accurately, especially for native valve endocarditis (NVE) and prosthetic material-related infection (PVE). The aim of this study is to evaluate the diagnostic performance of 18F-FDG PET in patients with suspected IE referred for PET/CT imaging. Purpose This retrospective study aims to assess the diagnostic value of 18F-FDG PET/CT for suspected NVE. Methods Data were collected from all patients who underwent 18F-FDG PET/CT for suspected IE at a tertiary center between May 2016 and January 2022. The final diagnosis of IE was established by consulting the Endocarditis team's diagnosis at the time of hospital discharge or death, after considering clinical, microbiological, and imaging information as well as clinical response. Sensitivity, specificity, and positive and negative predictive values of 18F-FDG PET/CT in diagnosing NVE were estimated. Results The study included 87 patients, of whom 32 had suspected NVE. The mean age was 62 +/- 19 years, and 62% were male. Of the patients with suspected NVE, 56% were male, with a median age of 53.5 (IQR 41.5-71) years. Fever was present in 84% of patients, and 16% had signs of heart failure. Laboratory tests showed a mean CRP of 16.2 mg/dL and a mean leucocyte count of 10.9 G/L. Among the suspected NVE patients, 8 had a definitive diagnosis of IE, with compatible findings observed in 18F-FDG PET/CT for 5 patients. The calculated sensitivity and specificity of 18F-FDG PET/CT for diagnosing NVE were 62.5% and 100%, respectively. Conclusion 18F-FDG PET/CT appears to be highly specific but not very sensitive for diagnosing NVE.