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INTRODUCTION

There has been a worldwide increase in implantation of cardiovascular devices, including cardiac implantable electronic devices (CIED), valve prostheses, left ventricular assist devices (LVAD), and vascular grafts. CIEDs, including pacemakers and implantable cardioverter defibrillators (ICDs) are the major devices installed. Almost one-half of the world's cardiac device installation is performed in the United States.1 Infection is a major complication after device installation, and, unfortunately, the increasing number of cardiac device procedures is exceeded by an even higher rate of increasing cases of device infection, mainly because of older age of the new device recipients with longer hospital stays and multiple comorbidities.2,3 Approximately 20%-30% of patients with CIED require device extraction and reinstallation, mainly due to infection,4 which is a major societal and medical burden. Infection of a foreign body device is also associated with a high risk of mortality. It has been reported that 12-week all-cause mortality was 35% in patients with a confirmed cardiac device infection, especially for those with methicillin-resistant S. aureus infection.5 One-year mortality was reported as high as 17% in endovascular infection patients even after device removal.6 Thus, early and accurate diagnosis of cardiac device infection is critical for prompt clinical decision making, such as intravenous antibiotics alone or device removal in a timely manner before significant damage occurs. Diagnosis of cardiac device infection remains a challenge for current diagnostic radiology tools. For example, CT or MRI suffers from metal artifacts and findings are nonspecific for infection. Transthoracic echocardiography (TTE) or transesophageal echocardiography (TEE) is limited to identification of intracardiac infection, and not useful for extracardiac source of infection. Although radiolabeled autologous white blood cell (WBC) scintigraphy has been used for infection evaluation, its sensitivity for device infection is variable.7,8 Thus, a scan with high sensitivity and accuracy is needed to facilitate the prompt and accurate diagnosis of cardiac device infection.

18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography (FDG PET/CT) is a functional imaging tool that targets the body's glucose utilization. Clinically it is mainly used for cancer staging, restaging, and posttreatment effect evaluation, as malignant cells have increased glucose uptake. On the other hand, preexisting inflammatory cells (macrophages, neutrophils, and lymphocytes) at an infection site also overexpress glucose transporters and could accumulate FDG. Bacteria at the infection site also rely on glucose as an energy source. FDG uptake in both inflammatory cells and bacteria at an infection site can then be detected by PET with high sensitivity. Compared to radiolabeled WBC scintigraphy, FDG PET/CT has the advantages of high spatial resolution with superior tomographic images, short procedure time (less than 2 hours, compared to 24 hours with WBC scan), less labor-intensive and lower radiation exposure. Prospectively conducted studies have shown that FDG PET/CT has a better accuracy in detecting infection for patients with joint prostheses than the WBC scan.9,10 Although most of the published results regarding the role of FDG PET/CT for ...

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