Relevance of cardiac imaging in the evolving landscape of infective endocarditis management

Abstract

Infective endocarditis (IE) is an increasingly recognized condition with high morbidity. Patients with atypical symptoms, culture-negative infections, and prosthetic cardiac devices and implants represent challenging populations to evaluate and manage. Recent major society guidelines have recommended the appropriate incorporation of multimodality imaging in the evaluation of these more complex IE cases. This article draws on the available literature regarding the different cardiac imaging modalities and discusses the role of multimodality imaging in IE.

Keywords: cardiac computed tomography; echocardiography; infective endocarditis; multimodality cardiovascular imaging; nuclear imaging; positron emission tomography; transesophageal echocardiography.

Figure 1.

Thirty-eight-year-old woman with a history of intravenous drug use and prior endocarditis requiring tricuspid valve replacement presents with 2 weeks of fevers and shortness of breath. Parasternal short-axis and four-chamber views on TTE (a, c) and TEE (b, d). A bioprosthetic tricuspid valve is seen by TTE but no vegetation can be clearly appreciated. In comparison, large mobile vegetation on the prosthetic tricuspid valve is clearly appreciated by TEE (arrow), with 3D reconstruction (e) yielding a vegetation size of 2.3 cm. TEE, transesophageal echocardiography; TTE, transthoracic echocardiography.

Figure 2.

Fifty-four-year-old man with a history of bacterial endocarditis and subsequent valve homograft implantation presenting with 3 weeks of fatigue. Transesophageal echocardiography (mid-esophageal short-axis view) shows a homograft prosthetic aortic valve with a large pseudoaneurysm/abscess cavity from the left coronary sinus (a, *) with abnormal flow on color Doppler (b). A large mobile vegetation with multiple fronds (arrow) is also seen inside the abscess cavity. A gated cardiac CT further defines the consequences of the infection. Sagittal images during diastole (c) and systole (d) show dynamic compression (circle) of the left main coronary artery between the pulmonary artery and the pseudoaneurysm cavity. Axial view (e) more clearly shows the extension of the large pseudoaneurysm from the left coronary sinus communicating with the left ventricle along the lateral wall (*). The large vegetation is again seen by CT (arrow). CT, computed tomography.

Figure 3.

Whole body ¹⁸F-FDG PET/CT of a patient with prior aortic root, ascending aorta, and arch replacement and aorto-bifemoral bypass graft, presenting with fevers and methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia. Note the intense heterogeneous uptake in the ascending aorta graft consistent with infection (a, blue arrows), in comparison to low-level more homogeneous uptake in the abdominal graft (b, green arrow) consistent with expected post-surgical changes. MSSA, methicillin-sensitive Staphylococcus aureus.