Prosthetic valve endocarditis and intracardiac device related endocarditis are difficult to diagnose and treat. Because of dense acoustic shadowing related to the components of prosthetic valves and cardiac implantable devices, role of echocardiography is often limited in the diagnosis of endocarditis in these situations. Of late Positron Emission Tomography Computed Tomography (PET CT) have been used more often in detecting foci of active inflammation / metabolism in infective endocarditis.
Study by María N. Pizzi et al has provided us with documentary evidence for adding PET CT to our diagnostic armamentarium in suspected cases of device or prosthetic valve related endocarditis. 18F-fluorodeoxyglucose (18F-FDG) PET CT was used in their study involving ninety two patients. Supplementing Dukes criteria with 18F-FDG PET CT increased the sensitivity from 52% to 91% with a slight fall in specificity from 95% to 89%. The authors further noted that reclassification from possible endocarditis to either definite or rejected category could be done in 95% which has great clinical significance. This would permit early initiation of antibiotic therapy in definite cases while avoiding unnecessary prolonged antibiotic therapy in rejected cases. There was an additional value in combining CT angiography with PET CT by enabling detection of larger number of anatomic lesions associated with active endocarditis than non enhanced PET CT.
1. Pizzi MN et al. Improving the Diagnosis of Infective Endocarditis in Prosthetic Valves and Intracardiac Devices with 18F-FDG-PET/CT-Angiography: Initial Results at an Infective Endocarditis Referral Center. Circulation. 2015; 132: 1113-1126.