Imaging techniques for diagnosis of infective endocarditis

Historically, the diagnosis of infective endocarditis (IE) has been difficult to establish with certainty. The classic tetrad of predisposing valvular disease, bacteremia, embolic phenomena, and evidence of an active endocardial process may be absent or incomplete. Various combinations of clinical criteria have been proposed [1,2]. The effectiveness of diagnostic criteria has been greatly enhanced by technological advancements in cardiac imaging, specifically echocardiography. This technique, which has been continually improved since its introduction 30 years ago, now provides excellent direct visualization of cardiac anatomy, enhancing sensitivity for diagnosis and identifying complications that may warrant valve surgery. The resulting improvement in structural characterization of the disease and its effects contributes to earlier diagnosis, better treatment, and avoidance of complications. This chapter describes the use of imaging techniques in the diagnosis and management of IE. Notable improvements in the spatial resolution of echocardiography over the past two decades have earned the technique a central role in the evaluation of patients for suspected IE. This application is a focus of the present chapter. The authors will also briefly discuss other modalities for imaging of IE: chest radiography, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear imaging.