Detection of extra-cardiac hypermetabolic foci by [18F]FDG PET/CT in case of infective endocarditis and post antibiotic therapy response assessment

The diagnosis of prosthetic valve endocarditis continues to present a diagnostic challenge, due to the lower sensitivity of the modified Duke criteria and a higher percentage of negative or inconclusive echocardiography results. Diagnostic delay might result in significant morbidity/mortality. Imaging modalities like 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography ([18F]FDG PET/CT), prove to be an added diagnostic modality in such cases, thus assisting the accuracy of diagnosis by the modified-Duke-criteria. [18F]FDG PET/CT can prove highly beneficial, provided proper preparation for adequate suppression of the physiological myocardial uptake is done prior to the scan, thus helping is semi-quantitative analysis of the infected focus. We herein, report a case of suspected infective endocarditis with known prior history of a prosthetic valve in situ where the diagnosis of infective endocarditis could not be established with conviction, despite the use of conventional modalities of imaging like 2D echocardiography. [18F]FDG PET/CT proved its mettle by determining the primary site of infection, as well as metastatic extra-cardiac infective foci, and thus avoiding morbidity arising out of delayed diagnosis.