18F-FDG PET/CT in Infective Endocarditis: Indications and Approaches for Standardization

Abstract

Purpose of Review Additional imaging modalities, such as FDG-PET/CT, have been included into the workup for patients with suspected infective endocarditis, according to major international guidelines published in 2015. The purpose of this review is to give an overview of FDG-PET/CT indications and standardized approaches in the setting of suspected infective endocarditis. Recent Findings There are two main indications for performing FDG-PET/CT in patients with suspected infective endocarditis: (i) detecting intracardiac infections and (ii) detection of (clinically silent) disseminated infectious disease. The diagnostic performance of FDG-PET/CT for intracardiac lesions depends on the presence of native valves, prosthetic valves, or implanted cardiac devices, with a sensitivity that is poor for native valve endocarditis and cardiac device-related lead infections, but much better for prosthetic valve endocarditis and cardiac device-related pocket infections. Specificity is high for all these indications. The detection of disseminated disease may also help establish the diagnosis and/or impact patient management. Summary Based on current evidence, FDG-PET/CT should be considered for detection of disseminated disease in suspected endocarditis. Absence of intracardiac lesions on FDG-PET/CT cannot rule out native valve endocarditis, but positive findings strongly support the diagnosis. For prosthetic valve endocarditis, standard use of FDG-PET/CT is recommended because of its high sensitivity and specificity. For implanted cardiac devices, FDG-PET/CT is also recommended, but should be evaluated with careful attention to clinical context, because its sensitivity is high for pocket infections, but low for lead infections. In patients with prosthetic valves with or without additional aortic prosthesis, combination with CTA should be considered. Optimal timing of FDG-PET/CT is important, both during clinical workup and technically (i.e., post tracer injection). In addition, procedural standardization is key and encompasses patient preparation, scan acquisition, reconstruction, subsequent analysis, and clinical interpretation. The recommendations discussed here will hopefully contribute to improved standardization and enhanced performance of FDG-PET/CT in the clinical management of patients with suspected infective endocarditis.

Cardiac Implantable Electronic Devices Infection Assessment, Diagnosis and Management: A Review of the Literature

“…In the study by Erba et al 99mTc-HMPAO WBC scintigraphy was 94% sensitive for both detection and localisation of CIED infection and associated complications, with a 95% negative predictive value to exclude device-associated infection during a febrile episode and sepsis [ 52 ]. 18F-FDG-PET/CT ( Figure 4 ), conversely, performs better for pocket infections than for lead infections: for pocket infections, pooled sensitivity and specificity were 93% and 98%, respectively, while for lead infections sensitivity was 65% although specificity was still high (88%) [ 53 ]. Aside from that, delayed image acquisition could increase 18F-FDG-PET/CT diagnostic accuracy in suspected CDRIE [ 54 ].…”

A role for artificial intelligence in molecular imaging of infection and inflammation

“…Previously, electrocardiogram (ECG)-gated motion correction of [ 18 F]-NaF uptake in coronary arteries in patients with myocardial infarction or stable angina had significant impact on lesion quantification (Rubeaux et al 2016). Along the same line for endocarditis, more accurate detection of small infectious foci in the plane of cardiac valves would increase detection rates and allow better co-localization with findings on ultrasound or cardiac CT, which improves diagnostic accuracy (Hove et al 2021).…”

“…Previously, electrocardiogram (ECG)-gated motion correction of [ 18 F]-NaF uptake in coronary arteries in patients with myocardial infarction or stable angina had significant impact on lesion quantification (Rubeaux et al 2016 ). Along the same line for endocarditis, more accurate detection of small infectious foci in the plane of cardiac valves would increase detection rates and allow better co-localization with findings on ultrasound or cardiac CT, which improves diagnostic accuracy (Hove et al 2021 ). On a more general note, deep-learning methods to reconstruct whole body PET images without the signal-derived input for attenuation and scatter correction by its CT component are reported (Yang et al 2021 ; Haggstrom et al 2019 ), with non-inferior image quality, but much faster reconstruction times.…”

Real-world assessment of the clinical utility of whole body 18F-FDG PET/CT in the diagnosis of infection

“…Due to high metabolic activity, inflammatory cells at foci of infection accumulate 18 F-FDG allowing for detection, confirmation and/or further assessment of infectious processes [ 1 ]. The use of 18 F-FDG PET/CT has been explored in infective endocarditis [ 2 , 3 ], febrile neutropenia [ 4 ], Staphylococcus aureus bacteremia [ 5 ], vascular graft infections [ 6 ], and invasive fungal infections [ 7 ] among several other applications [ 8 , 9 ]. The diagnostic yield and clinical impact of 18 F-FDG PET/CT varies based on context and has ranged widely [ 4 , 5 , 10 – 12 ].…”

“…Despite a mounting number of reports exploring the use of 18 F-FDG PET/CT for specific indications like S . aureus bacteremia [ 5 ] or intracardiac infections (e.g., infective endocarditis) [ 2 , 3 ], fewer studies have aimed to capture the full spectrum of 18 F-FDG PET/CT use for evaluation of infections in a real-world context. To evaluate the impact of 18 F-FDG PET/CT on diagnosis of infections and changes in antimicrobial management, we performed a single-center, retrospective review of 18 F-FDG PET/CT studies performed for evaluation of suspected infections in hospitalized patients.…”