Early diagnosis of cardiac implantable electronic device generator pocket infection using ¹⁸F-FDG-PET/CT

The Role of the 18F-FDG PET/CT in the Management of Patients Suspected of Cardiac Implantable Electronic Devices' Infection

Background: Infection of Cardiac Implantable Electronic Devices (CIEDI) is a real public health problem. The main aim of this study was to determine the diagnostic performance of 18F-FDG PET/CT in the diagnosis of CIEDI. Methods: A total of 48 patients, who performed 18F-FDG PET/CT for the clinical suspicion of CIEDI were retrospectively analyzed; all patients were provided with a model with procedural recommendations before the exam. Sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy (DA) of 18F-FDG PET/CT were calculated; the reproducibility of qualitative analysis was assessed with Cohen's κ test. The semi-quantitative parameters (SUVmax, SQR and TBR) were evaluated in CIEDI+ and CIEDI- patients using the Student' t-test; ROC curves were elaborated to detect cut-off values. The trend of image quality with regards to procedural recommendation adherence was evaluated. Results: Se, Sp, PPV, NPV and DA were respectively 96.2%, 81.8%, 86.2%, 94.7% and 89.6%. The reproducibility of qualitative analysis was excellent (K = 0.89). Semiquantitative parameters resulted statistically different in CIEDI+ and CIEDI- patients. Cut-off values were SUVmax = 2.625, SQR = 3.766 and TBR = 1.29. Trend curves showed increasing image quality due to adherence to procedural recommendations. Conclusions:18F-FDG-PET/CT is a valid tool in the management of patients suspected of CIEDI and adherence to procedural recommendations improves its image quality.

Multimodality Imaging Diagnosis in Infective Endocarditis

Imaging is an important tool in the diagnosis and management of infective endocarditis (IE). Echocardiography is an essential examination, especially in native valve endocarditis (NVE), but its diagnostic accuracy is reduced in prosthetic valve endocarditis (PVE). The diagnostic ability is superior for transoesophageal echocardiography (TEE), but a negative test cannot exclude PVE. Both transthoracic echocardiography (TTE) and TEE can provide normal or inconclusive findings in up to 30% of cases, especially in patients with prosthetic devices. New advanced non-invasive imaging tests are increasingly used in the diagnosis of IE. Nuclear medicine imaging techniques have demonstrated their superiority over TEE for the diagnosis of PVE and cardiac implantable electronic device infective endocarditis (CIED-IE). Cardiac computed tomography angiography imaging is useful in PVE cases with inconclusive TTE and TEE investigations and for the evaluation of paravalvular complications. In the present review, imaging tools are described with their values and limitations for improving diagnosis in NVE, PVE and CIED-IE. Current knowledge about multimodality imaging approaches in IE and imaging methods to assess the local and distant complications of IE is also reviewed. Furthermore, a potential diagnostic work-up for different clinical scenarios is described. However, further studies are essential for refining diagnostic and management approaches in infective endocarditis, addressing limitations and optimizing advanced imaging techniques across different clinical scenarios.

Radionuclide Imaging of Infective Endocarditis

Infective endocarditis (IE) is associated with high morbidity and mortality. Early diagnosis is crucial for adequate patient management. Due to difficulties in the diagnosis, a multidisciplinary discussion in addition to the integration of clinical signs, microbiology data, and imaging data is used. Imaging, including echocardiography, molecular imaging techniques, and coronary CT angiography (CTA) is central to detect infections involving heart valves and implanted cardiovascular devices, also allowing for early detection of septic emboli and metastatic. This article describes the main clinical application of white blood cell SPECT/CT and [¹⁸F]FDG-PET/CT and CTA in IE and infections associated with cardiovascular implantable electronic devices.

Advances in Molecular Imaging in Infective Endocarditis

Infective endocarditis (IE) is a growing epidemiological challenge. Appropriate diagnosis remains difficult due to heterogenous etiopathogenesis and clinical presentation. The disease may be followed by increased mortality and numerous diverse complications. Developing molecular imaging modalities may provide additional insights into ongoing infection and support an accurate diagnosis. We present the current evidence for the diagnostic performance and indications for utilization in current guidelines of the hybrid modalities: single photon emission tomography with technetium99m-hexamethylpropyleneamine oxime-labeled autologous leukocytes (^99mTc-HMPAO-SPECT/CT) along with positron emission tomography with fluorodeoxyglucose (¹⁸F-FDG PET/CT). The role of molecular imaging in IE diagnostic work-up has been constantly growing due to technical improvements and the increasing evidence supporting its added diagnostic and prognostic value. The various underlying molecular processes of ^99mTc-HMPAO-SPECT/CT as well as ¹⁸F-FDG PET/CT translate to different imaging properties, which should be considered in clinical practice. Both techniques provide additional diagnostic value in the assessment of patients at risk of IE. Nuclear imaging should be considered in the IE diagnostic algorithm, not only for the insights gained into ongoing infection at a molecular level, but also for the determination of the optimal clinical therapeutic strategies.

The Emerging Role of FDG PET/CT in Diagnosing Endocarditis and Cardiac Device Infection

Infective endocarditis and cardiac implantable electronic device infection (CIEDI) have witnessed an increasing incidence in clinical practice and associated with increasing health care expenditure. Expanding indications of CIED in various cardiovascular conditions have also contributed to the surge of these infections. Early diagnosis of these infections is associated with a favorable prognosis. Given the lack of a single definitive diagnostic method and the limitations of echocardiography, which is considered a central diagnostic imaging modality, additional imaging modalities are required. Recent studies have highlighted the diagnostic utility of FDG PET and CT. In this review article, we discuss the existing limitations of echocardiography, acquisition protocols of PET/CT, and indications of these advanced imaging modalities in infective endocarditis and CIEDI diagnosis.

Molecular Imaging of Valvular Diseases and Cardiac Device Infection

The use of positron emission tomography imaging with 18F-fluorodeoxyglucose in the diagnostic workup of patients with suspected prosthetic valve endocarditis and cardiac device infection (implantable electronic device and left ventricular assist device) is gaining momentum in clinical practice. However, in the absence of prospective randomized trials, guideline recommendations about 18F-fluorodeoxyglucose positron emission tomography in this setting are currently largely based on expert opinion. Measurement of aortic valve microcalcification occurring as a healing response to valvular inflammation using 18F-sodium fluoride positron emission tomography represents another promising clinical approach, which is associated with both the risk of native valve stenosis progression and bioprosthetic valve degeneration in research trials. In this review, we consider the role of molecular imaging in cardiac valvular diseases, including aortic stenosis and valvular endocarditis, as well as cardiac device infections.

Evaluation of lead-based echodensities on transesophageal echocardiogram in patients with cardiac implantable electronic devices

INTRODUCTION

Transesophageal echocardiography (TEE) is recommended to rule out endocarditis in patients with cardiac implantable electronic devices (CIED). A lead-based echodensity (LBE), however, is often found on TEE in patients with a CIED and may not represent an infection. We sought to evaluate the predictors, characteristics, and clinical significance of LBEs seen on TEE in patients with a CIED.

METHODS

Patients with a CIED were retrospectively identified from a database using International Classification of Diseases (ICD)-9/ICD-10 codes and were cross-matched with Current Procedural Terminology codes for a TEE. Clinical and follow-up data were collected. A blinded echo board-certified cardiologist reviewed all TEEs.

RESULTS

Out of the 231 patients in the cohort, 191 had TEE performed for a noninfection-related indication while 40 TEEs were part of an endocarditis workup. A total of 50 LBEs were identified, and a majority were in the noninfection cohort. Systemic anticoagulant use in the noninfection cohort was associated with a decreased odds of having LBE on TEE (odds ratio [OR] of 0.23 [95% confidence interval [CI]: 0.06-0.60, p = .003]). Lead dwell time in the noninfection cohort was associated with an increased odds of having LBE on TEE (OR 1.21 (95% CI: 1.04-1.39, p = .009]).

CONCLUSION

In our cohort of patients who had TEE for noninfection indications we found that systemic anticoagulant use is associated with fewer LBEs on TEEs, suggesting possible thrombin fibrin composition of LBE.

Infective Endocarditis in High-Income Countries

Infective endocarditis remains an illness that carries a significant burden to healthcare resources. In recent times, there has been a shift from Streptococcus sp. to Staphylococcus sp. as the primary organism of interest. This has significant consequences, given the virulence of Staphylococcus and its propensity to form a biofilm, rendering non-surgical therapy ineffective. In addition, antibiotic resistance has affected treatment of this organism. The cohorts at most risk for Staphylococcal endocarditis are elderly patients with multiple comorbidities. The innovation of transcatheter technologies alongside other cardiac interventions such as implantable devices has contributed to the increased risk attributable to this cohort. We examined the pathophysiology of infective endocarditis carefully. Inter alia, the determinants of Staphylococcus aureus virulence, interaction with host immunity, as well as the discovery and emergence of a potential vaccine, were investigated. Furthermore, the potential role of prophylactic antibiotics during dental procedures was also evaluated. As rates of transcatheter device implantation increase, endocarditis is expected to increase, especially in this high-risk group. A high level of suspicion is needed alongside early initiation of therapy and referral to the heart team to improve outcomes.

Rate of Cardiovascular Implantable Electronic Device-Related Infection at a Tertiary Hospital in Saudi Arabia: A Retrospective Cohort Study

Introduction

Cardiovascular implantable electronic devices (CIEDs) are long-term cardiac treatments that address a variety of cardiac diseases. In the recent years, a steady growth has been noticed in CIEDs, mainly due to expanding indications for their usage. Possible device-related infection, whether pocket or systemic, which leads to high morbidity and mortality, is one of the most worrying complications. In addition, there are limited studies conducted on the topic of CIED infection rate and their clinical presentation both regionally and locally.

Methods

In this retrospective cohort study, we reviewed the medical records of all patients with CIEDs who presented to our medical center (implanted, followed up, or referred to our hospital) between January 2016 and January 2019.The medical records were extracted from the BestCare electronic medical records system (ezCaretech Co, Seoul, Korea). All consecutive patients were included as we had no exclusion criteria.

Results

During the three years of the study period, a total of 612 patients with CIEDs were identified at our medical center. Among this cohort, 436 subjects (71.2%) were male and 176 (28.8%) were female. Thirty-four patients experienced device-related infections from among the total patient population (n = 612) who presented with CIEDs between January 2016 and January 2019, for a total rate of 5.6%. Of the infected patients, 29 (85%) presented with local infections and five (15%) presented with systemic infections.

Conclusion

The infection rate of 5.6% observed in this study was higher than expected. Therefore, we conclude that action should be taken to reduce infection rates at our medical center to at least that seen in prior studies or below that, if possible. Moreover, we found that CIED infections were often caused by Staphylococcus species and commonly affected the elderly and patients with chronic diseases such as diabetes and hypertension. Most of the identified cases were local infections, although systemic infections were common in those with renal disease. Further studies are needed to control the risk factors and to better understand the role of antibiotics, antiseptic prophylaxis, and other methods in avoiding CIED infection and associated complications.

Alternative Nuclear Imaging Tools for Infection Imaging

Purpose of Review

Cardiovascular infections are serious disease associated with high morbidity and mortality. Their diagnosis is challenging, requiring a proper management for a prompt recognition of the clinical manifestations, and a multidisciplinary approach involving cardiologists, cardiothoracic surgeons, infectious diseases specialist, imagers, and microbiologists. Imaging plays a central role in the diagnostic workout, including molecular imaging techniques. In this setting, two different strategies might be used to image infections: the first is based on the use of agents targeting the microorganism responsible for the infection. Alternatively, we can target the components of the pathophysiological changes of the inflammatory process and/or the host response to the infectious pathogen can be considered. Understanding the strength and limitations of each strategy is crucial to select the most appropriate imaging tool.

Recent Findings

Currently, multislice computed tomography (MSCT) and nuclear imaging (¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography, and leucocyte scintigraphy) are part of the diagnostic strategies. The main role of nuclear medicine imaging (PET/CT and SPECT/CT) is the confirmation of valve/CIED involvement and/or associated perivalvular infection and the detection of distant septic embolism. Proper patients’ preparation, imaging acquisition, and reconstruction as well as imaging reading are crucial to maximize the diagnostic information.

Summary

In this manuscript, we described the use of molecular imaging techniques, in particular WBC imaging, in patients with infective endocarditis, cardiovascular implantable electronic device infections, and infections of composite aortic graft, underlying the strength and limitations of such approached as compared to the other imaging modalities.

Let there be light! The meteoric rise of cardiac imaging

Imaging plays a central role in modern cardiovascular practice. It is a field characterised by exciting technological advances that have shaped our understanding of pathology and led to major improvements in patient diagnosis and care. The UK has played a key international role in the development of this subspecialty and is the current home to many of the leading global centres in multimodality cardiovascular imaging. In this short review, we will outline some of the key contributions of the British Cardiovascular Society and its members to this rapidly evolving field and look at how this relationship may continue to shape future cardiovascular practice.

Soft Bioelectronics Based on Nanomaterials

Recent advances in nanostructured materials and unconventional device designs have transformed the bioelectronics from a rigid and bulky form into a soft and ultrathin form and brought enormous advantages to the bioelectronics. For example, mechanical deformability of the soft bioelectronics and thus its conformal contact onto soft curved organs such as brain, heart, and skin have allowed researchers to measure high-quality biosignals, deliver real-time feedback treatments, and lower long-term side-effects in vivo. Here, we review various materials, fabrication methods, and device strategies for flexible and stretchable electronics, especially focusing on soft biointegrated electronics using nanomaterials and their composites. First, we summarize top-down material processing and bottom-up synthesis methods of various nanomaterials. Next, we discuss state-of-the-art technologies for intrinsically stretchable nanocomposites composed of nanostructured materials incorporated in elastomers or hydrogels. We also briefly discuss unconventional device design strategies for soft bioelectronics. Then individual device components for soft bioelectronics, such as biosensing, data storage, display, therapeutic stimulation, and power supply devices, are introduced. Afterward, representative application examples of the soft bioelectronics are described. A brief summary with a discussion on remaining challenges concludes the review.

18F-FDG positron emission tomography/computed tomography of cardiac implantable electronic device infections

BACKGROUND

The diagnosis of cardiac implantable electronic device (CIED) infection is challenging because of its variable presentations. We studied the value of 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in the detection of CIED infection.

METHODS AND RESULTS

Thirty patients with suspected CIED infection underwent 18F-FDG-PET/CT. The control group was ten patients with asymptomatic CIED who underwent cancer-related 18F-FDG-PET/CT. 18F-FDG-PET/CT was evaluated visually, semiquantitatively as maximum standardized uptake value (SUVmax) and target-to-background ratio (TBR). Final diagnosis of CIED infection was based on clinical and bacteriological data. 18F-FDG-PET/CT was visually positive in all 9 patients with recent (≤ 8 weeks) implantation of CIED, but only 4 had confirmed CIED infection. 18F-FDG-PET/CT was true positive in 9 out of 21 cases with remote implantation of CIED and false positive in 3 (14.3%) cases. 18F-FDG-PET/CT was also false positive in 3 (30%) cases of control group. The SUVmax of the pocket area was significantly higher in patients with CIED infection than in the control group (4.8 ± 2.4 vs 2.0 ± .8, P < .001). By using the cut-off value of TBR ≥ 1.8, sensitivity of 18F-FDG-PET/CT for the diagnosis of CIED infection in patients with remote implantation was 90% and specificity 73%, PPV 75%, and NPV 89%.

CONCLUSIONS

18F-FDG-PET/CT is a sensitive but nonspecific method in the diagnosis of CIED infection.

Incidence of lead erosion in a real-world cohort and a case of successful treatment with an antimicrobial mesh

Cardiac implantable electronic device (CIED)-related infections are a major complication of CIED therapy and associated with high morbidity and mortality. The aim of the present study was to evaluate the incidence of lead erosion as one cause of the CIED-related infections and to provide detailed information about the therapy of two cases of lead erosion. We retrospectively screened the database of a large clinic specialized on patients with CIED (HIZ BERLIN Herzschrittmacher- und ICD-Zentrum, Berlin, Germany) for cases of lead erosion between 2015 and 2020. A total of 5971 outpatients were treated at the HIZ BERLIN - including 4782 patients with a one- or two-chamber pacemaker, 837 patients with an implantable cardioverter defibrillator (ICD) and 352 patients with a biventricular device for cardiac resynchronization therapy (CRT). The incidence of lead erosion was 0.033%. As one of the two patients, who suffered from lead erosions, had no signs of systemic infection, the patient received local therapy with an antimicrobial mesh and intravenous antibiotics. After twelve months, he showed a good clinical outcome without ongoing or recurring infection. In conclusion, the incidence of lead erosion is low. In case of lead erosions without signs of systemic infection, an antimicrobial mesh might be implanted as an off-label use in patients that decline complete device removal.

The Diagnostic Value of 99mTc-HMPAO-Labelled White Blood Cell Scintigraphy and 18F-FDG PET/CT in Cardiac Device-Related Infective Endocarditis-A Systematic Review

(1) Background: Treatment of cardiac arrhythmias and conduction disorders with the implantation of a cardiac implantable electronic device (CIED) may lead to complications. Cardiac device-related infective endocarditis (CDRIE) stands out as being one of the most challenging in terms of its diagnosis and management. Developing molecular imaging modalities may provide additional insights into CDRIE diagnosis. (2) Methods: We performed a systematic literature review to critically appraise the evidence for the diagnostic performance of the following hybrid techniques: single photon emission tomography with technetium99m-hexamethylpropyleneamine oxime–labeled autologous leukocytes (99mTc-HMPAO-SPECT/CT) and positron emission tomography with fluorodeoxyglucose (18F-FDG PET/CT). An analysis was performed in accordance with PRISMA and GRADE criteria and included articles from PubMed, Embase and Cochrane databases. (3) Results: Initially, there were 2131 records identified which had been published between 1971–2021. Finally, 18 studies were included presenting original data on the diagnostic value of 99mTc-HMPAO-SPECT/CT or 18F-FDG PET/CT in CDRIE. Analysis showed that these molecular imaging modalities provide high diagnostic accuracy and their inclusion in diagnostic criteria improves CDRIE work-up. (4) Conclusions: 99mTc-HMPAO-SPECT/CT and 18F-FDG PET/CT provide high diagnostic value in the identification of patients at risk of CDRIE and should be considered for inclusion in the CDRIE diagnostic process.

Imaging of Cardiac Device-Related Infection

Cardiac devices are frequently used in different cardiovascular conditions for the purpose of morbidity or mortality prevention. These include cardiac implantable electronic devices (CIED) like permanent pacemakers and implantable cardiac defibrillators, ventricular assistance devices (VADs), left atrial appendage occlusion (LAAO) devices like the Watchman™, atrial and ventricular septal occluders like the Amplatzer™, among others. In the past years, there has been an increase in the development of these devices as a result of a rise in the number of indications for implantation, paired with the aging and more medically complex patient population. This has led to an increase in the incidence of cardiac device-related infections, one of the most feared and serious complications which is associated with significant morbidity, mortality and financial burden. Accurate diagnosis of cardiac device-related infections is essential given the management implications which often involve removal of the infected device, removal of other prosthetic material and long-term antimicrobial therapy. Clinical and laboratory data are useful diagnostic tools but multimodality imaging is often necessary. The recently published 2020 European Heart Rhythm Association International Consensus document, which is endorsed by many expert societies, has recommended the use of multimodality imaging for the diagnosis of CIED infections. (1) This allows better disease characterization by identifying abnormal fluid collections and guiding aspiration for both diagnostic and therapeutic purposes (i.e. soft tissue ultrasound and computed tomography), evaluation for local extent of disease (i.e. transesophageal echocardiogram to evaluate for concomitant infective endocarditis), embolic manifestation of disease (i.e. computed tomography and magnetic resonance imaging) and metabolic tissue characterization (positron emission tomography and tagged white blood cell scan). (2) In addition, computed tomography (CT) allows for pre-procedural planning which has shown to be associated with better procedural outcomes.

Infection of cardiac prosthetic valves and implantable electronic devices: early diagnosis and treatment

There has been a recent rise in the use of implantable cardiac devices, mostly valves but also electronic ones, such as pacemakers, and implantable defibrillators. The increasing use of these devices had as a consequence the raised incidence of endocarditis, an infrequent but morbid complication of these procedures. Thus, early diagnosis of the implantable cardiac devices related infection and endocarditis became pivotal for appropriate management. For diagnostic purposes, the modified Duke criteria are widely used, which are based on clinical and imaging findings, in addition to serological analyses and blood cultures. 18F-fluoro-2-deoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is a recently employed method in order to improve the early diagnosis of endocarditis as well as infection of the implantable device. It is likely, that combining the modified Duke criteria with the FDG PET/CT, will increase the sensitivity and specificity of diagnosis and will guide the treating physician to an early and appropriate management.

State-of-the-art narrative review: multimodality imaging in electrophysiology and cardiac device therapies

Cardiac electrophysiology procedures have evolved to provide improvement in morbidity and mortality for many patients. Cardiac resynchronization therapy (CRT), implantable cardioverter/defibrillator (ICD) placement and lead extraction procedures are proven procedures, associated with significant reductions in patient morbidity and mortality as well as improved quality of life. The applications and optimization of these therapies are an evolving field. The optimal use and outcomes of cardiac electrophysiology procedures require a multidisciplinary approach to patient selection, device selection, and procedural planning. Cardiac imaging using echocardiography plays a key role in selection of patients for CRT therapy, for guidance of left ventricular (LV) lead placement, and for optimization of atrioventricular pacing delays in patients with CRT. Cardiac computed tomography (CT) is an important tool in assessment of lead perforation, as well as assessing risk of lead extraction and procedural planning. Cardiac magnetic resonance imaging (MRI) is an important adjunct to transthoracic echocardiography for patient selection and risk stratification for defibrillator therapy for multiple disease states including ischemic cardiomyopathy, hypertrophic cardiomyopathy, cardiac sarcoidosis, and arrhythmogenic right ventricular cardiomyopathy (ARVC). Cardiac positron emission tomography (PET) is a useful adjunct to the diagnosis of device infections as well as inflammatory conditions including cardiac sarcoidosis. Our review attempts to summarize the contemporary roles of multimodality imaging in CRT therapy, ICD therapy and lead extraction therapy.

State of the art of 18F-FDG PET/CT application in inflammation and infection: a guide for image acquisition and interpretation

AIM

The diagnosis, severity and extent of a sterile inflammation or a septic infection could be challenging since there is not one single test able to achieve an accurate diagnosis. The clinical use of 18F-fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography/computed tomography (PET/CT) imaging in the assessment of inflammation and infection is increasing worldwide. The purpose of this paper is to achieve an Italian consensus document on [¹⁸F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases, such as osteomyelitis (OM), prosthetic joint infections (PJI), infective endocarditis (IE), prosthetic valve endocarditis (PVE), cardiac implantable electronic device infections (CIEDI), systemic and cardiac sarcoidosis (SS/CS), diabetic foot (DF), fungal infections (FI), tuberculosis (TBC), fever and inflammation of unknown origin (FUO/IUO), pediatric infections (PI), inflammatory bowel diseases (IBD), spine infections (SI), vascular graft infections (VGI), large vessel vasculitis (LVV), retroperitoneal fibrosis (RF) and COVID-19 infections.

METHODS

In September 2020, the inflammatory and infectious diseases focus group (IIFG) of the Italian Association of Nuclear Medicine (AIMN) proposed to realize a procedural paper about the clinical applications of [¹⁸F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases. The project was carried out thanks to the collaboration of 13 Italian nuclear medicine centers, with a consolidate experience in this field. With the endorsement of AIMN, IIFG contacted each center, and the pediatric diseases focus group (PDFC). IIFG provided for each team involved, a draft with essential information regarding the execution of [¹⁸F]FDG PET/CT or PET/MRI scan (i.e., indications, patient preparation, standard or specific acquisition modalities, interpretation criteria, reporting methods, pitfalls and artifacts), by limiting the literature research to the last 20 years. Moreover, some clinical cases were required from each center, to underline the teaching points. Time for the collection of each report was from October to December 2020.

RESULTS

Overall, we summarized 291 scientific papers and guidelines published between 1998 and 2021. Papers were divided in several sub-topics and summarized in the following paragraphs: clinical indications, image interpretation criteria, future perspectivess and new trends (for each single disease), while patient preparation, image acquisition, possible pitfalls and reporting modalities were described afterwards. Moreover, a specific section was dedicated to pediatric and PET/MRI indications. A collection of images was described for each indication.

CONCLUSIONS

Currently, [¹⁸F]FDG PET/CT in oncology is globally accepted and standardized in main diagnostic algorithms for neoplasms. In recent years, the ever-closer collaboration among different European associations has tried to overcome the absence of a standardization also in the field of inflammation and infections. The collaboration of several nuclear medicine centers with a long experience in this field, as well as among different AIMN focus groups represents a further attempt in this direction. We hope that this document will be the basis for a "common nuclear physicians' language" throughout all the country.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40336-021-00445-w.

Usefulness of 18F-FDG PET/CT in Patients with Cardiac Implantable Electronic Device Suspected of Late Infection

The presence of a cardiovascular implantable electronic device (CIED) can be burdened by complications such as late infections that are associated with significant morbidity and mortality and require immediate and effective treatment. The aim of this study was to evaluate the role of ¹⁸F-fluorodeoxyglucose positron-emission tomography/computed tomography (¹⁸F-FDG PET/CT) in patients with suspected CIED infection. Fifteen patients who performed a ¹⁸F-FDG PET/CT for suspicion of CIED infection were retrospectively analyzed; 15 patients, with CIED, that underwent ¹⁸F-FDG PET/CT for oncological reasons, were also evaluated. Visual qualitative analysis and semi-quantitative analysis were performed. All patients underwent standard clinical management regardless ¹⁸F-FDG PET/CT results. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) resulted as 90.91%, 75%, 86.67%, 90.91% and 75% respectively. Maximum standardized uptake values (SUV_max) and semi-quantitative ratio (SQR) were collected and showed differences statistically significant between CIED infected patients and those who were not. Exploratory cut-off values were derived from receiver operating characteristic (ROC) curves for SUV_max (2.56) and SQR (4.15). This study suggests the clinical usefulness of ¹⁸F-FDG PET/CT in patients with CIED infection due to its high sensitivity, repeatability and non-invasiveness. It can help the clinicians in decision making, especially in patients with doubtful clinical presentation. Future large-scale and multicentric studies should be conducted to establish precise protocols about ¹⁸F-FDG PET/CT performance.

Multimodality Imaging in the Diagnostic Work-Up of Endocarditis and Cardiac Implantable Electronic Device (CIED) Infection

Infective endocarditis (IE) is a serious cardiac condition, which includes a wide range of clinical presentations, with varying degrees of severity. The diagnosis is multifactorial and a proper characterization of disease requires the identification of the primary site of infection (usually the cardiac valve) and the search of secondary systemic complications. Early depiction of local complications or distant embolization has a great impact on patient management and prognosis, as it may induce to aggressive antibiotic treatment or, in more advanced cases, cardiac surgery. In this setting, the multimodality imaging has assumed a pivotal role in the clinical decision making and it requires the physician to be aware of the advantages and disadvantages of each imaging technique. Echocardiography is the first imaging test, but it has several limitations. Therefore, the integration with other imaging modalities (computed tomography, magnetic resonance imaging, nuclear imaging) becomes often necessary. Different strategies should be applied depending on whether the infection is suspected or already ascertained, whether located in native or prosthetic valves, in the left or right chambers, or if it involves an implanted cardiac device. In addition, detection of extracardiac IE-related lesions is crucial for a correct management and treatment. The aim of this review is to illustrate strengths and weaknesses of the various methods in the most common clinical scenarios.

Multimodality Imaging in Infective Endocarditis: An Imaging Team Within the Endocarditis Team

Infective endocarditis (IE) is a complex disease with cardiac involvement and multiorgan complications. Its prognosis depends on prompt diagnosis that leads to an aggressive therapeutic management combining antibiotic therapy and early cardiac surgery when indicated. However, IE diagnosis always poses a challenge, and echocardiography remains diagnostically imperfect in cases of prosthetic valve IE or cardiac implantable electronic device infection. In recent years, other imaging modalities (computed tomography, magnetic resonance imaging, nuclear imaging) have experienced significant technical improvements, and their application to the detection of cardiac and extracardiac IE-related lesions seems to be a strategic way forward in the management of patients with suspected IE. However, the scientific evidence in the literature remains limited; current guidelines address the use of the multimodality imaging in the field of IE with caution; the incremental value of each technique and their combinations is debated; and their use varies across countries. Despite these limitations, healthcare providers and surgeons should be aware of the possibilities offered by the multimodal imaging approach when appropriate. Here, we emphasize the value of a multidisciplinary heart valve team, the endocarditis team, underlining the importance of cardiac and extracardiac imaging experts in playing a key role in informing the diagnosis and management of patients with IE. Illustrative cases, critical appraisal of contemporary data, and conceptual and practical suggestions for clinicians that may help to improve the prognosis of patients with IE are provided in this review article.

The role of 99mTc-HMPAO-labelled white blood cell scintigraphy in the diagnosis of cardiac device-related infective endocarditis

Aims

The hybrid technique of single-photon emission tomography and computed tomography with technetium99m-hexamethylpropyleneamine oxime–labelled leucocytes (99mTc-HMPAO-SPECT/CT) is an emerging diagnostic technique in patients with cardiac device-related infective endocarditis (CDRIE). This prospective study assessed the 99mTc-HMPAO-SPECT/CT diagnostic profile and its added value to the modified Duke criteria (mDuke) in CDRIE diagnostic work-up.

Methods and results

The study examined 103 consecutive patients with suspected CDRIE, who underwent 99mTc-HMPAO-SPECT/CT. Diagnostic accuracy was calculated based on a final clinical CDRIE diagnosis, including microbiology, echocardiography, and a 6-month follow-up. Subsequently, we compared the diagnostic value of the initial mDuke classification with a classification including 99mTc-HMPAO-SPECT/CT positive results as an additional major CDRIE criterion: mDuke-SPECT/CT.

Overall, CDRIE was diagnosed in 31 (31%) patients, whereas 35 (34%) 99mTc-HMPAO-SPECT/CT were positive. 99mTc-HMPAO-SPECT/CT was characterized by 86% accuracy, 0.69 Cohen’s kappa coefficient, 84% sensitivity, 88% specificity, 93% negative, and 74% positive predictive values. The original mDuke displayed 83% accuracy, 0.52 kappa, whereas mDuke-SPECT/CT had 88% accuracy, and 0.73 kappa. Compared with mDuke, mDuke-SPECT/CT showed significantly higher sensitivity (87% vs. 48%, P &lt; 0.001). According to mDuke, 49.5% of patients had possible CDRIE, and after reclassification, that figure dropped to 37%. Furthermore, having assessed the diagnosis categorization improvement following the incorporation of 99mTc-HMPAO-SPECT/CT, the net reclassification index value was found to be 31.4%.

Conclusion

In patients with CDRIE, 99mTc-HMPAO-SPECT/CT provides high diagnostic accuracy, whereas a negative scan excludes CDRIE with high probability. Inclusion of 99mTc-HMPAO-SPECT/CT into mDuke diagnostic criteria yields significantly higher sensitivity and a reduction in possible CDRIE diagnoses.

The Diagnosis and Treatment of Pacemaker-Associated Infection

BACKGROUND

Approximately 105 000 cardiac electronic devices are newly implanted in Germany each year. Germany has the highest implantation rate with respect to population of any European country. Infections in cardiac implants are serious complications, with an associated in-hospital mortality of 5-15%. It is thus very important to optimize the diagnostic and therapeutic strategies by which such infections can be detected early and treated effectively.

METHODS

This review is based on pertinent publications retrieved by a search in PubMed, with special attention to the current recommendations of international medical specialty societies.

RESULTS

According to the international literature, the incidence of device-associated infection is 1.7% (in six months) for implanted defibrillators and 9.5% (in two years) for resynchronization devices. No absolute figures on infection rates are available for Germany. Infection can involve either the site where the impulse generator is implanted or the intravascular portion of the electrodes. The most important elements of the diagnostic evaluation are: assessment of the local findings; pathogen identification by culture of peripheral blood, swabs of the infected site, or material recovered at surgery; and transesophageal echocardiography to detect endocarditic deposits on the electrodes or cardiac valves. The treatment consists of appropriate antibiotic administration and the complete removal of all foreign material. These special extractions are generally performed via the transvenous route. With the aid of various sheath systems, the procedure can be carried out safely and effectively, with a success rate above 95% and a complication rate below 3%. The indications for the implantation of a new device after eradication of the infection should be critically reassessed.

CONCLUSION

Untreated infection carries a high mortality. Evaluation and treatment according to a standardized clinical algorithm facilitate correct and timely diagnosis and the choice of an appropriate therapeutic strategy.

Diagnostic Impact of 18 F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography and White Blood Cell SPECT/Computed Tomography in Patients With Suspected Cardiac Implantable Electronic Device Chronic Infection

Background:

Cardiac implantable electronic devices (CIEDs) chronic infection diagnosis is challenging because the clinical presentation is frequently misleading and echocardiography may be inconclusive. The aim of this study was to evaluate the diagnostic value of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (CT) and radiolabeled white blood cells single photon emission CT/CT in a cohort of patients who underwent both scans for suspicion of CIED infection and inconclusive routine investigations.

Methods:

Forty-eight consecutive patients with suspicion of CIED infection who underwent both 18 F-fluorodeoxyglucose positron emission tomography/CT and white blood cell single photon emission CT/CT in a time span ≤30 days were retrospectively included. The final diagnosis of CIED infection by the endocarditis expert team was based on the modified Duke-Li classification at the end of follow-up. 18 F-Fluorodeoxyglucose positron emission tomography/CT and white blood cell single photon emission CT/CT scans were independently analyzed blinded to the patients’ medical record.

Results:

In the overall study population, the diagnostic sensitivity, specificity, positive predictive value, and negative predictive value were respectively 80%, 91%, 80%, and 91% for 18 F-fluorodeoxyglucose positron emission tomography/CT and 60%, 100%, 100%, and 85% for white blood cell single photon emission CT/CT. Addition of a positive nuclear imaging scan as a major criterion markedly improved the Duke-Li classification at admission. Semiquantitative parameters did not allow to discriminate between definite and rejected CIED infection. Prolonged antibiotic therapy before imaging tended to decrease the sensitivity for both techniques.

Conclusions:

Nuclear imaging can improve the diagnostic performances of the Duke-Li score at admission in a selected population of patients with suspected CIED infection, particularly when the infection was initially graded as possible. Whenever possible, imaging should be performed before or early after antibiotic initiation.

Role of 18F-FDG PET/CT in the diagnosis of cardiovascular implantable electronic device infections: A meta-analysis

OBJECTIVE

We performed a meta-analysis evaluating the use of fluorine-18-fluorodeoxyglucose (18F-FDG) positron-emission tomography (PET)/computed tomography (CT) in the diagnosis of cardiovascular implantable electronic device (CIED) infections.

BACKGROUND

PET/CT may be helpful in the diagnosis of CIED infection, particularly in patients with the absence of localizing signs or definitive echocardiographic findings.

METHODS

PubMed, Embase, Cochrane library, CINAHL, Web of Knowledge, and www.clinicaltrials.gov from January 1990 to April 2017 were searched for studies evaluating the accuracy of PET/CT in the diagnosis of CIED infections.

RESULTS

Overall, 14 studies involving 492 patients were included in the meta-analysis. The pooled sensitivity of PET/CT for diagnosis of CIED infection was 83% (95% CI 78%-86%) and the pooled specificity was 89% (95% CI 84%-94%). PET/CT demonstrated a higher sensitivity of 96% (95% CI 86%-99%) and specificity of 97% (95% CI 86%-99%) for diagnosis of pocket infections. Diagnostic accuracy for lead infections or CIED-IE was lower with pooled sensitivity of 76% (95% CI 65%-85%) and specificity of 83% (95% CI 72%-90%).

CONCLUSION

Use of PET/CT in the evaluation of CIED infection has both a high sensitivity (83%) and specificity (89%) and deserves consideration in the management of selected patients with suspected CIED infections.

Occult bacteraemia in cardiac implantable electronic device patients: a review of diagnostic workflow and mandatory therapy

: Cardiac implantable electronic device (CIED) implantation has greatly increased, with an associated exponential increase in CIED infections (CDIs). Cardiac device related infective endocarditis (CDRIE) has high morbidity and mortality: approximately 10-21%. Therefore, a prompt diagnosis and radical treatment of CDRIE are needed; transvenous lead extraction (TLE) is the mainstay for the complete healing, even if associated with wide logistic problems, high therapeutic costs and high mortality risk for patients. Some criticisms about the value of Duke criteria and their limitations for the diagnosis of CDRIE are known. The significance of classic laboratory data, transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE), considered in the Duke score, are reviewed and critically discussed in this article, with regard to the specific field of the diagnosis of CDI. The need for new techniques for achieving the diagnostic reliability has been well perceived by physicians, and additional techniques have been introduced in the new European Society of Cardiology (ESC) and British Heart Rhythm Society (BHRS) guidelines on infective endocarditis. These suggested techniques, such as 18-Fluorodeoxyglucose PET/computed tomography (FDG-PET/CT), white blood cell PET (WBC PET) and lung multislice CT (MSCT), are also discussed in the study. This short review is intended as an extensive summary of the diagnostic workflow in cases of CDI and will be useful for readers who want to know more about this issue.

Infective Endocarditis in the Elderly: Diagnostic and Treatment Options

Infective endocarditis (IE) is an uncommon, life-threatening systemic disorder with significant morbidity and persistently high mortality. The age of the peak incidence of IE has shifted from 45 years in the 1950s to 70 years at the present time, and elderly people have a five-fold higher risk of IE than the general adult population. Elderly IE patients demonstrate a higher prevalence of coagulase-negative staphylococci, enterococci and Streptococcus bovis, and lower rates of infection by viridans group streptococci. Methicillin resistance is more prevalent in elderly patients as a consequence of increased nosocomial acquisition. The elderly are a vulnerable group in whom diagnosis is often difficult on account of non-specific presenting features and where higher prevalence of comorbidities contributes to adverse outcomes. Treatment of older patients with IE presents specific challenges associated with prolonged antibiotic therapy, and access to surgery may be denied on account of advanced age and attendant comorbidities. This practical review covers all aspects of elderly IE, including clinical and microbiological diagnosis and appropriate diagnostic procedures, initial antibiotic selection, antibiotic prophylaxis, considerations about antibiotic therapy and surgery.

Cardiovascular Implantable Electronic Device Infections

Infections associated with cardiac implantable electronic devices are increasing and are associated with significant morbidity and mortality. This article reviews the epidemiology, microbiology, and risk factors for acquisition of these infections. The complex diagnostic and management strategies associated with these serious infections are reviewed with an emphasis on recent updates and advances, as well as existing controversies. Additionally, the latest in preventative strategies are reviewed.

Contribution of PET imaging to mortality risk stratification in candidates to lead extraction for pacemaker or defibrillator infection: a prospective single center study

PURPOSE

¹⁸F-FDG PET/CT is an emerging technique for diagnosis of cardiac implantable electronic devices infection (CIEDI). Despite the improvements in transvenous lead extraction (TLE), long-term survival in patients with CIEDI is poor. The aim of the present study was to evaluate whether the extension of CIEDI at ¹⁸F-FDG PET/CT can improve prediction of survival after TLE.

METHODS

Prospective, monocentric observational study enrolling consecutive candidates to TLE for a diagnosis of CIEDI. ¹⁸F-FDG PET/CT was performed in all patients prior TLE.

RESULTS

There were 105 consecutive patients with confirmed CIEDI enrolled. An increased ¹⁸F-FDG uptake was limited to cardiac implantable electrical device (CIED) pocket in 56 patients, 40 patients had a systemic involvement. We had nine negative PET in patients undergoing prolonged antimicrobial therapy (22.5 ± 14.0 days vs. 8.6 ± 13.0 days; p = 0.005). Implementation of ¹⁸F-FDG PET/CT in modified Duke Criteria lead to reclassification of 23.8% of the patients. After a mean follow-up of 25.0 ± 9.0 months, 31 patients died (29.5%). Patients with CIED pocket involvement at ¹⁸F-FDG PET/CT presented a better survival independently of presence/absence of systemic involvement (HR 0.493, 95%CI 0.240-0.984; p = 0.048). After integration of ¹⁸F-FDG PET/CT data, absence of overt/hidden pocket involvement in CIEDI and a (glomerular filtration rate) GFR < 60 ml/min were the only independent predictors of mortality at long term.

CONCLUSIONS

Patient with CIEDI and a Cold Closed Pocket (i.e., a CIED pocket without skin erosion/perforation nor increased capitation at ¹⁸F-FDG PET/CT) present worse long-term survival. Patient management can benefit by systematic adoption of pre-TLE ¹⁸F-FDG PET/CT through improved identification of CIED related endocarditis (CIEDIE) and hidden involvement of CIED pocket.

Transvenous Lead Extractions: Current Approaches and Future Trends

The use of cardiac implantable electronic devices (CIEDs) has continued to rise along with indications for their removal. When confronted with challenging clinical scenarios such as device infection, malfunction or vessel occlusion, patients often require the prompt removal of CIED hardware, including associated leads. Recent advancements in percutaneous methods have enabled physicians to face a myriad of complex lead extractions with efficiency and safety. Looking ahead, emerging technologies hold great promise in making extractions safer and more accessible for patients worldwide. This review will provide the most up-to-date indications and procedural approaches for lead extractions and insight on the future trends in this novel field.

Approach to Diagnosis of Cardiovascular Implantable-Electronic-Device Infection

Device infection remains a significant challenge as clinical indications for cardiovascular implantable electronic device (CIED) therapy continue to expand beyond the prevention and treatment of cardiac arrhythmias. Patients receiving CIED therapy are now older and have significant comorbidities, placing them at higher risk of complications, including infection. CIED infection warrants complete device removal, as retention is associated with an unacceptably high risk of relapse and increased mortality. However, accurate diagnosis of CIED infections remains a significant challenge that is based on a combination of findings on physical examination, microbiological and laboratory testing, and advanced imaging, such as transesophageal echocardiography or positron emission tomography. Isolating a causative pathogen and performing susceptibility testing are crucial for appropriate choice, route, and duration of antimicrobial therapy. In this review, we present an evidence-based approach to diagnosis of CIED infection.

Recommendations on nuclear and multimodality imaging in IE and CIED infections

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 [¹⁸F]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 [¹⁸F]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.

The "3M" Approach to Cardiovascular Infections: Multimodality, Multitracers, and Multidisciplinary

Cardiovascular infections are associated with high morbidity and mortality. Early diagnosis is crucial for adequate patient management, as early treatment improves the prognosis. The diagnosis cannot be made on the basis of a single symptom, sign, or diagnostic test. Rather, the diagnosis requires a multidisciplinary discussion in addition to the integration of clinical signs, microbiology data, and imaging data. The application of multimodality imaging, including molecular imaging techniques, has improved the sensitivity to detect infections involving heart valves and vessels and implanted cardiovascular devices while also allowing for early detection of septic emboli and metastatic infections before these become clinically apparent. In this review, we describe data supporting the use of a Multimodality, Multitracer, and Multidisciplinary approach (the 3M approach) to cardiovascular infections. In particular, the role of white blood cell SPECT/CT and [¹⁸F]FDG PET/CT in most prevalent and clinically relevant cardiovascular infections will be discussed. In addition, the needs of advanced hybrid equipment, dedicated imaging acquisition protocols, specific expertise for image reading, and interpretation in this field are discussed, emphasizing the need for a specific reference framework within a Cardiovascular Multidisciplinary Team Approach to select the best test or combination of tests for each specific clinical situation.

18F-FDG-PET/CT Angiography for the Diagnosis of Infective Endocarditis

PURPOSE OF REVIEW

This article reviews the current imaging role of ¹⁸F-fluordeoxyglucose positron emission computed tomography (¹⁸F-FDG-PET/CT) combined with cardiac CT angiography (CTA) in infective endocarditis and discusses the strengths and limitations of this technique.

RECENT FINDINGS

The diagnosis of infective endocarditis affecting prosthetic valves and intracardiac devices is challenging because echocardiography and, therefore, the modified Duke criteria have well-recognized limitations in this clinical scenario. The high sensitivity of ¹⁸F-FDG-PET/CT for the detection of infection associated with the accurate definition of structural damage by gated cardiac CTA in a combined technique (PET/CTA) has provided a significant increase in diagnostic sensitivity for the detection of IE. PET/CTA has proven to be a useful diagnostic tool in patients with suspected infective endocarditis. The additional information provided by this technique improves diagnostic performance in prosthetic valve endocarditis when it is used in combination with the Duke criteria. The findings obtained in PET/CTA studies have been included as a major criterion in the recently updated diagnostic algorithm in infective endocarditis guidelines.

Metabolic Imaging of Infection

Metabolic imaging has come to occupy a prominent place in the diagnosis and management of microbial infection. Molecular probes available for infection imaging have undergone a rapid evolution starting with nonspecific agents that accumulate similarly in infection, sterile inflammation, and neoplastic tissue and then extending to more targeted probes that seek to identify specific microbial species. This focus review describes the metabolic and molecular imaging techniques currently available for clinical use in infection imaging and those that have demonstrated promising results in preclinical studies with the potential for clinical applications.

Challenges in Infective Endocarditis

Infective endocarditis is defined by a focus of infection within the heart and is a feared disease across the field of cardiology. It is frequently acquired in the health care setting, and more than one-half of cases now occur in patients without known heart disease. Despite optimal care, mortality approaches 30% at 1 year. The challenges posed by infective endocarditis are significant. It is heterogeneous in etiology, clinical manifestations, and course. Staphylococcus aureus, which has become the predominant causative organism in the developed world, leads to an aggressive form of the disease, often in vulnerable or elderly patient populations. There is a lack of research infrastructure and funding, with few randomized controlled trials to guide practice. Longstanding controversies such as the timing of surgery or the role of antibiotic prophylaxis have not been resolved. The present article reviews the challenges posed by infective endocarditis and outlines current and future strategies to limit its impact.

Positron Emission Tomography and Single-Photon Emission Computed Tomography Imaging in the Diagnosis of Cardiac Implantable Electronic Device Infection: A Systematic Review and Meta-Analysis

BACKGROUND

The use of cardiac implantable electronic devices (CIED) is increasing, and their associated infections result in significant morbidity and mortality. The introduction of better cardiac imaging techniques could be useful for diagnosing this condition and guiding therapy. Our objective was to systematically assess the diagnostic accuracy of Fluor-18-fluorodeoxyglucose positron emission tomography and computed tomography, labeled leukocyte scintigraphy (LS), and Gallium-67 citrate scintigraphy for the diagnosis of CIED infection.

METHODS AND RESULTS

A systematic review of the literature and meta-analysis on the use of all 3 modalities in CIED infection were conducted. Pooled sensitivity, specificity, and summary receiver operating characteristic curves of each imaging modalities were determined. The literature search identified 2493 articles. A total of 13 articles (11 studies for ¹⁸F-FDG PET-CT and 2 for LS), met the inclusion criteria. No studies for ⁶⁷Ga citrate scintigraphy met the inclusion criteria. The pooled sensitivity of ¹⁸F-FDG PET-CT for the diagnosis of CIED infection was 87% (95% CI, 82%-91%) and pooled specificity was 94% (95% CI, 88%-98%). The summary receiver operating characteristic curve analysis demonstrated good overall accuracy, with an area under the curve of 0.935. There were insufficient data to do a meta-analysis for LS, but both studies reported sensitivity above 90% and specificity of 100%.

CONCLUSIONS

Both ¹⁸F-FDG PET-CT and LS yield high sensitivity, specificity, and accuracy, and thus seem to be useful for the diagnosis of CIED infection, based on robust data for ¹⁸F-FDG PET-CT but limited data for LS. When available,¹⁸F-FDG PET-CT may be preferred.