Recommendations on nuclear and multimodality imaging in IE and CIED infections

Abstract

In the latest update of the European Society of Cardiology (ESC) guidelines for the management of infective endocarditis (IE), imaging is positioned at the centre of the diagnostic work-up so that an early and accurate diagnosis can be reached. Besides echocardiography, contrast-enhanced CT (ce-CT), radiolabelled leucocyte (white blood cell, WBC) SPECT/CT and [F]FDG PET/CT are included as diagnostic tools in the diagnostic flow chart for IE. Following the clinical guidelines that provided a straightforward message on the role of multimodality imaging, we believe that it is highly relevant to produce specific recommendations on nuclear multimodality imaging in IE and cardiac implantable electronic device infections. In these procedural recommendations we therefore describe in detail the technical and practical aspects of WBC SPECT/CT and [F]FDG PET/CT, including ce-CT acquisition protocols. We also discuss the advantages and limitations of each procedure, specific pitfalls when interpreting images, and the most important results from the literature, and also provide recommendations on the appropriate use of multimodality imaging.

Guidelines in review: Comparison of ESC and AHA guidance for the diagnosis and management of infective endocarditis in adults. Are the differences clinically relevant? The European perspective

“…6,7 Besides echocardiography, contrast-enhanced computed tomography (CT), magnetic resonance imaging (MRI), radiolabeled white blood cell (WBC) singlephoton emission computed tomography (SPECT)/CT, and 18 F-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography (PET)/CT are evolving as important supplementary methods for patients with suspected IE and diagnostic difficulties, particularly in patients with suspected PVE. 8 Multimodality imaging may improve identification of endocardial involvement and extra cardiac complications of IE.…”

“…8 The article described the technical and practical aspects of these techniques as well as reviewed the literature regarding diagnostic accuracy, advantages, limitations, and pitfalls. Several reports have shown promising results for 18 F-FDG PET/CT and WBC SPECT/CT imaging in IE.…”

“…Several reports have shown promising results for 18 F-FDG PET/CT and WBC SPECT/CT imaging in IE. 8,10 When 18 F-FDG PET/CT is used to diagnose cardiac infection, patient preparation is very important in order to suppress physiological tracer uptake in the myocardium. These measures include high-fat low carbohydrate diet, prolonged fasting, and heparin injection prior to the scan.…”

“…These measures include high-fat low carbohydrate diet, prolonged fasting, and heparin injection prior to the scan. 8 A meta-analysis of published studies with adequate cardiac preparation including 407 patients found that the overall pooled sensitivity of 18 F-FDG PET/CT in patients with suspected IE is 81%, increasing to 85% when only PVE is considered. The overall pooled specificity was 90%, and 81% when only PVE was considered.…”

“…10 However, disadvantages of WBC SPECT/CT include the need for manipulation of blood products for labeling and a more time-consuming protocol. 8,10 Additional benefit of nuclear imaging is that extracardiac complications, such as septic emboli and metastatic infection, are commonly detected by 18 F-FDG PET/CT or WBC SPECT/CT that can contribute to the diagnosis of IE and have therapeutic implications. 8,10 In one study, extracardiac findings were seen in 60% of patients, and in 15% these lesions were previously unknown and considered of clinical relevance.…”