Recommendations on nuclear and multimodality imaging in IE and CIED infections

Contemporary Role of Positron Emission Tomography (PET) in Endocarditis: A Narrative Review

Endocarditis, a serious infectious disease, remains a diagnostic challenge in contemporary clinical practice. The advent of advanced imaging modalities has contributed significantly to the improved understanding and management of this complex disease. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) imaging has shown remarkable potential in improving the diagnostic accuracy of endocarditis. In the update of the Modified Duke Criteria, in 2023, The International Society for Cardiovascular Infectious Diseases (ISCVID) Working Group recognized specific 18F-FDG PET/CT findings as a major diagnostic criterion, particularly in patient with prosthetic valve endocarditis. The ability of PET to visualize metabolic activity allows for the identification of infective foci and could differentiate between infective and non-infective processes. This review examines the clinical utility of PET in differentiating infective endocarditis from other cardiovascular pathologies, highlighting its sensitivity and specificity in detecting native and prosthetic valve infections, including patients with transcatheter aortic valve implantation (TAVI), cardiac implantable devices (CIEDs), and left ventricular assistance devices (LVAD). Also, practical aspects and indications are illustrated to optimize the quality of imaging and reduce potential false positive results. In conclusion, the current use of PET in endocarditis has become a valuable diagnostic tool; as technological advances continue, PET will play an increasingly important role in the multidisciplinary approach to the management of endocarditis.

Infective endocarditis associated with left atrial appendage occlusion device: a contemporary systematic review

BACKGROUND

Data are limited regarding infective endocarditis (IE) complicating left atrial appendage occlusion (LAAO) device procedures. This systematic review examines the etiology, diagnosis, and management of infective endocarditis (IE) following LAAO.

METHODS

A comprehensive search of six databases was performed between 2007 and 2022. In selecting studies, articles were included if they provided information about IE complicating LAAO, with relevant clinical and imaging details. Articles were excluded if they were editorials, study protocols, letters, or abstracts.

RESULTS

We identified seven cases of IE complicating LAAO published between 2007 and 2022, from the United States and Europe, highlighting the exceedingly rare reported incidence of the condition. Staphylococcus aureus is the predominant organism implicated in LAAO infections. Echocardiography is a key imaging modality for diagnosing LAAO IE. Both antibiotic therapy and surgical intervention in appropriate patients are important for managing LAAO device-related IE.

CONCLUSIONS

The limited data in the current literature regarding LAAO IE underscores the need for prospective clinical trials to establish evidence-based guidelines for infection prophylaxis, diagnosis, and management. Our findings emphasize the importance of vigilance for device-related infections, especially as the use of LAAO devices continues to grow worldwide.

A systematic review for the evidence of recommendations and guidelines in hybrid nuclear cardiovascular imaging

OBJECTIVES

This study aimed to evaluate the level of evidence of expert recommendations and guidelines for clinical indications and procedurals in hybrid nuclear cardiovascular imaging.

METHODS

From inception to August 2023, a PubMed literature analysis of the latest version of guidelines for clinical hybrid cardiovascular imaging techniques including SPECT(/CT), PET(/CT), and PET(/MRI) was performed in two categories: (1) for clinical indications for all-in primary diagnosis; subgroup in prognosis and therapy evaluation; and for (2) imaging procedurals. We surveyed to what degree these followed a standard methodology to collect the data and provide levels of evidence, and for which topic systematic review evidence was executed.

RESULTS

A total of 76 guidelines, published between 2013 and 2023, were included. The evidence of guidelines was based on systematic reviews in 7.9% of cases, non-systematic reviews in 47.4% of cases, a mix of systematic and non-systematic reviews in 19.7%, and 25% of guidelines did not report any evidence. Search strategy was reported in 36.8% of cases. Strengths of recommendation were clearly reported in 25% of guidelines. The notion of external review was explicitly reported in 23.7% of cases. Finally, the support of a methodologist was reported in 11.8% of the included guidelines.

CONCLUSION

The use of evidence procedures for developing for evidence-based cardiovascular hybrid imaging recommendations and guidelines is currently suboptimal, highlighting the need for more standardized methodological procedures.

Emerging and Re-Emerging Pathogens in Valvular Infective Endocarditis: A Review

Infective endocarditis (IE) is a microbial infection of the endocardial surface, most commonly affecting native and prosthetic valves of the heart. The epidemiology and etiology of the disease have evolved significantly over the last decades. With a growing elderly population, the incidence of degenerative valvopathies and the use of prosthetic heart valves have increased, becoming the most important predisposing risk factors. This change in the epidemiology has caused a shift in the underlying microbiology of the disease, with Staphylococci overtaking Streptococci as the main causative pathogens. Other rarer microbes, including Streptococcus agalactiae, Pseudomonas aeruginosa, Coxiella burnetti and Brucella, have also emerged or re-emerged. Valvular IE caused by these pathogens, especially Staphylococcus aureus, is often associated with a severe clinical course, leading to high rates of morbidity and mortality. Therefore, prompt diagnosis and management are crucial. Due to the high virulence of these pathogens and an increased incidence of antimicrobial resistances, surgical valve repair or replacement is often necessary. As the epidemiology and etiology of valvular IE continue to evolve, the diagnostic methods and therapies need to be progressively advanced to ensure satisfactory clinical outcomes.

The 2023 new European guidelines on infective endocarditis: main novelties and implications for clinical practice

The 2023 European Society of Cardiology (ESC) guidelines for the management of infective endocarditis update the previous 2015 guidelines with main novelties in five areas: (1) antibiotic prevention for high-risk patients, and prevention measures for intermediate-risk and high-risk patients; (2) diagnosis with emphasis on multimodality imaging to assess cardiac lesions of infective endocarditis' (3) antibiotic therapy allowing an outpatient antibiotic treatment for stabilized, uncomplicated cases; (4) cardiac surgery with an emphasis on early intervention without delay for complicated cases; and (5) shared management decision by the endocarditis team. Most evidence came from observational studies and expert opinions. The guidelines strongly support a patient-centred approach with a shared decision process by a multidisciplinary team that should be implemented either in tertiary referral centres, becoming heart valve centres, and referral centres. A continuous sharing of data is warranted in the hospitals' network between heart valve centres, which are used for referrals for complicated cases of infective endocarditis, and referral centres, which should be able to manage uncomplicated cases of infective endocarditis.

Infective Endocarditis: The role of PET imaging in diagnosis and management

Positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG) has recently emerged as an increasingly used alternative and supplementary imaging modality for the diagnosis of infective endocarditis. 18F-FDG PET/CT imaging for IE is given a Class I recommendation (level of evidence B) and is therefore recommended in cases of possible prosthetic valve IE to both detect valvular lesions, as well as confirm the diagnosis of IE. They have also given a class I recommendation (level of evidence B) for brain and whole-body 18F-FDG PET/CT and/or MRI imaging to detect peripheral lesions for patients with either native or prosthetic valve IE. Molecular imaging is playing an increasingly important role in the diagnosis and management of patients with IE. The important role of 18F-FDG PET/CT imaging has been acknowledged by recent guideline updates. These advanced imaging tests are not supplanting the role of echocardiography in the diagnostic pathway for IE. Rather, they are additional tools that are available where the diagnosis is complicated, difficult, or uncertain.

18F-FDG PET/CT and Radiolabeled Leukocyte SPECT/CT Imaging for the Evaluation of Cardiovascular Infection in the Multimodality Context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations From ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multisocietal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multifocal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

New developments in infective endocarditis

Infective endocarditis is a continually evolving disease. Present-day patients differ significantly from those treated a few decades ago: they tend to be older and have more comorbidities and health care-related episodes, while new groups of patients have emerged with new types of endocarditis, such as those affecting patients with percutaneous valve prostheses. There have also been changes in diagnostic techniques. Although transthoracic and transesophageal echocardiography are still the most commonly used imaging modalities, other techniques, such as 3-dimensional transesophageal ultrasound, cardiac computed tomography, and nuclear medicine tests (PET/CT and SPECT/CT), are increasingly used for diagnosing both the disease and its complications. In recent years, there have also been significant developments in antibiotic therapy. Currently, several treatment strategies are available to shorten the hospital phase of the disease in selected patients, which can reduce the complications associated with hospitalization, improve the quality of life of patients and their families, and reduce the health care costs of the disease. This review discusses the main recent epidemiological, diagnostic and therapeutic developments in infective endocarditis.

18F-FDG PET/CT and radiolabeled leukocyte SPECT/CT imaging for the evaluation of cardiovascular infection in the multimodality context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations from ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

Role of multimodality imaging in infective endocarditis: A comparison of the major society guidelines in the United States and Europe

Infective endocarditis (IE) is a life-threatening condition, and early diagnosis and management are critical. There is emerging evidence on the role of advanced imaging modalities including dedicated cardiac computed tomography (CCT), and 18F-fluorodeoxyglucose positron emission tomography (PET). The updated 2023 European Society of Cardiology (ESC) guidelines have emphasized increased utilization of multimodality imaging in the diagnosis and management of IE. In this review, we elaborate on recent recommendations from the updated 2023 ESC guidelines, with comparisons to the current American College of Cardiology (ACC)/American Heart Association (AHA) guidelines, focusing on multimodality imaging in IE.

18F-FDG PET/CT and radiolabeled leukocyte SPECT/CT imaging for the evaluation of cardiovascular infection in the multimodality context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations from ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

18F-FDG PET/CT and radiolabeled leukocyte SPECT/CT imaging for the evaluation of cardiovascular infection in the multimodality context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations from ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

Novel Diagnostic Methods for Infective Endocarditis

Infective endocarditis (IE) remains a dangerous disease and continues to have a high mortality rate. Unfortunately, despite continuous improvements in diagnostic methods, in many cases, blood cultures remain negative, and the pathogen causing endocarditis is unknown. This makes targeted therapy and the selection of appropriate antibiotics impossible. Therefore, we present what methods can be used to identify the pathogen in infective endocarditis. These are mainly molecular methods, including PCR and MGS, as well as imaging methods using radiotracers, which offer more possibilities for diagnosing IE. However, they are still not widely used in the diagnosis of IE. The article summarizes in which cases we should choose them and what we are most hopeful about in further research into the diagnosis of IE. In addition, registered clinical trials that are currently underway for the diagnosis of IE are also presented.

One Fell Swoop: Septic Muscle Embolism and Central Venous Catheter Infection Imaged with [18F] Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

We describe the case of a 43-year-old female with hereditary hemochromatosis, previously without cardiac issues, who presented with a severe fever (>40 to 41 °C) to our hospital. Initial assessments, including transthoracic echocardiography, showed no typical signs of infective endocarditis. A contrast-enhanced CT scan revealed a hypodense area in the right subscapular muscle, alongside pleural thicknesses. Due to the critical condition, a central venous catheter (CVC) was implanted for immediate intravenous treatment. Subsequent blood cultures, positive for Staphylococcus aureus, and transesophageal echocardiography led to a diagnosis of multivalvular infective endocarditis (MIE). Subsequently, the patient underwent positron emission tomography/computed tomography (PET/CT) with [18F]Fluorodeoxyglucose ([18F]FDG), which detected increased tracer incorporation in the muscle lesion, CVC, and pleural thicknesses. The final diagnosis was CVC infection and septic embolism to the subscapular muscle in a patient with pleuritis. This case showcases the critical role of [18F]FDG PET/CT as whole-body imaging modality in diagnosing and managing complex infective cases.

Contemporary applications of multimodality imaging in infective endocarditis

INTRODUCTION

Infective endocarditis (IE) is an increasingly important condition with significant morbidity and mortality. With advancements in cardiovascular interventions including prosthetic valve implantation and utilization of intracardiac devices, the prevalence of IE is rising in the modern era. Early detection and management of this condition are critical.

AREAS COVERED

This review presents a contemporary review of the applications of multi-modality imaging in IE, taking a comparative approach of the various imaging modalities.

EXPERT OPINION

Transthoracic and transesophageal echocardiography are essential imaging modalities in establishing the diagnosis of IE, as well as evaluating for complications of IE. Other imaging modalities such as cardiac computed tomography and nuclear imaging play an important role as adjuvant imaging modalities for the evaluation of IE, particularly in prosthetic valve IE and cardiovascular implantable device associated IE. It is crucial to understand the strengths, weaknesses, and clinical application of each imaging modality, to improve the diagnosis, management, and outcomes of patients with IE.

18F- FDG PET/CT in reclassifying the probable diagnosis of IE - A review

In the diagnosis of infective endocarditis (IE), Modified Duke's criteria, coupled with clinical suspicion, serve as the guiding framework. For cases involving prosthetic valve endocarditis and infections affecting implantable devices, the use of metabolic imaging with 18 F-FDG PET/CT scans has gained prominence, as per the recommendations of the European Society of Cardiology guidelines. This imaging modality enhances sensitivity and specificity by identifying infective foci within the heart and extracardiac locations. Early utilization of these scans is crucial for confirming or ruling out IE, although caution is required to mitigate false positive responses, especially in the presence of ongoing inflammatory activity. A standardized ratio of ≥2.0 between FDG uptake around infected tissues and the blood pool has demonstrated a sensitivity of 100 % and specificity of 91 %. It is noteworthy that the sensitivity of FDG PET/CT varies, being lower for native valve and lead infections but considerably higher for prosthetic valve and pulse generator infections. This review provides a comprehensive overview of the advantages offered by FDG PET/CT in achieving a definitive diagnosis of IE.

Imaging in patients with cardiovascular implantable electronic devices: part 2-imaging after device implantation. A clinical consensus statement of the European Association of Cardiovascular Imaging (EACVI) and the European Heart Rhythm Association (EHRA) of the ESC

Cardiac implantable electronic devices (CIEDs) improve quality of life and prolong survival, but there are additional considerations for cardiovascular imaging after implantation-both for standard indications and for diagnosing and guiding management of device-related complications. This clinical consensus statement (part 2) from the European Association of Cardiovascular Imaging, in collaboration with the European Heart Rhythm Association, provides comprehensive, up-to-date, and evidence-based guidance to cardiologists, cardiac imagers, and pacing specialists regarding the use of imaging in patients after implantation of conventional pacemakers, cardioverter defibrillators, and cardiac resynchronization therapy (CRT) devices. The document summarizes the existing evidence regarding the role and optimal use of various cardiac imaging modalities in patients with suspected CIED-related complications and also discusses CRT optimization, the safety of magnetic resonance imaging in CIED carriers, and describes the role of chest radiography in assessing CIED type, position, and complications. The role of imaging before and during CIED implantation is discussed in a companion document (part 1).

The Role of Multimodality Imaging in Patients with Congenital Heart Disease and Infective Endocarditis

Infective endocarditis (IE) represents an important medical challenge, particularly in patients with congenital heart diseases (CHD). Its early and accurate diagnosis is crucial for effective management to improve patient outcomes. Multimodality imaging is emerging as a powerful tool in the diagnosis and management of IE in CHD patients, offering a comprehensive and integrated approach that enhances diagnostic accuracy and guides therapeutic strategies. This review illustrates the utilities of each single multimodality imaging, including transthoracic and transoesophageal echocardiography, cardiac computed tomography (CCT), cardiovascular magnetic resonance imaging (CMR), and nuclear imaging modalities, in the diagnosis of IE in CHD patients. These imaging techniques provide crucial information about valvular and intracardiac structures, vegetation size and location, abscess formation, and associated complications, helping clinicians make timely and informed decisions. However, each one does have limitations that influence its applicability.

Variability of [18F]FDG-PET/LDCT reporting in vascular graft and endograft infection

PURPOSE

18F-fluoro-D-deoxyglucose positron emission tomography with low dose and/or contrast enhanced computed tomography ([18F]FDG-PET/CT) scan reveals high sensitivity for the diagnosis of vascular graft and endograft infection (VGEI), but lower specificity. Reporting [18F]FDG-PET/CT scans of suspected VGEI is challenging, reader dependent, and reporting standards are lacking. The aim of this study was to evaluate variability of [18F]FDG-PET/low dose CT (LDCT) reporting of suspected VGEI using a proposed standard reporting format.

METHODS

A retrospective cohort study was conducted including all patients with a suspected VGEI (according to the MAGIC criteria) without need for urgent surgical treatment who underwent an additional [18F]FDG-PET/LDCT scan between 2006 and 2022 at a tertiary referral centre. All [18F]FDG-PET/LDCT reports were scored following pre-selected criteria that were formulated based on literature and experts in the field. The aim was to investigate the completeness of [18F]FDG-PET/LDCT reports for diagnosing VGEI (proven according to the MAGIC criteria) and to evaluate if incompleteness of reports influenced the diagnostic accuracy.

RESULTS

Hundred-fifty-two patients were included. Median diagnostic interval from the index vascular surgical procedure until [18F]FDG-PET/LDCT scan was 35.5 (7.3-73.3) months. Grafts were in 65.1% located centrally and 34.9% peripherally. Based on the pre-selected reporting criteria, 45.7% of the reports included all items. The least frequently assessed criterion was FDG-uptake pattern (40.6%). Overall, [18F]FDG-PET/LDCT showed a sensitivity of 91%, a specificity of 72%, and an accuracy of 88% when compared to the gold standard (diagnosed VGEI). Lower sensitivity and specificity in reports including ≤ 8 criteria compared to completely evaluated reports were found (83% and 50% vs. 92% and 77%, respectively).

CONCLUSION

Less than half of the [18F]FDG-PET/LDCT reports of suspected VGEI met all pre-selected criteria. Incompleteness of reports led to lower sensitivity and specificity. Implementing a recommendation with specific criteria for VGEI reporting is needed in the VGEI-guideline update. This study provides a first recommendation for a concise and complete [18F]FDG-PET/LDCT report in patients with suspected VGEI.

Endocarditis in critically ill patients: a review

PURPOSE OF REVIEW

To summarize the advances in literature that support the best current practices regarding infective endocarditis (IE) in critically ill patients.

RECENT FINDINGS

IE due to rheumatic diseases has decreased significantly, and in fact, the majority of cases are associated with degenerative valvopathies, prosthetic valves, and cardiovascular implantable electronic devices. The Duke criteria were recently updated, addressing the increasing incidence of new risk factors for IE, such as IE associated with the use of endovascular cardiac implantable electronic devices and transcatheter implant valves. The presence of organ dysfunction, renal replacement therapies, or extracorporeal membrane oxygenation should be considered in the choice of drug and dosage in critically ill patients with suspected or confirmed IE. As highlighted for other severe infections, monitoring of therapeutic antibiotic levels is a promising technique to improve outcomes in critically ill patients with organ dysfunction.

SUMMARY

The diagnostic investigation of IE must consider the current epidemiological criteria and the diagnostic particularities that these circumstances require. A careful evaluation of these issues is necessary for the prompt clinical or surgical management of this infection.

Myocardial Functional Imaging in Pediatric Nuclear Cardiology

The role of nuclear medicine in pediatric cardiology has grown rapidly over the years, providing useful functional and prognostic information and playing a complementary role to morphological imaging in the evaluation of myocardial perfusion, cardiovascular inflammation and infections, and cardiac sympathetic innervation. The aim of this narrative review is to summarize and highlight the most important evidence on pediatric nuclear cardiology, describing clinical applications and the possibilities, advantages, and limitations of nuclear medicine techniques. Moreover, a special focus will be given to the minimization of radiation exposure in pediatric nuclear cardiology imaging, a critical topic in children.

Hot spot imaging in cardiovascular diseases: an information statement from SNMMI, ASNC, and EANM

This information statement from the Society of Nuclear Medicine and Molecular Imaging, American Society of Nuclear Cardiology, and European Association of Nuclear Medicine describes the performance, interpretation, and reporting of hot spot imaging in nuclear cardiology. The field of nuclear cardiology has historically focused on cold spot imaging for the interpretation of myocardial ischemia and infarction. Hot spot imaging has been an important part of nuclear medicine, particularly for oncology or infection indications, and the use of hot spot imaging in nuclear cardiology continues to expand. This document focuses on image acquisition and processing, methods of quantification, indications, protocols, and reporting of hot spot imaging. Indications discussed include myocardial viability, myocardial inflammation, device or valve infection, large vessel vasculitis, valve calcification and vulnerable plaques, and cardiac amyloidosis. This document contextualizes the foundations of image quantification and highlights reporting in each indication for the cardiac nuclear imager.

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.

Imaging of Endocarditis and Cardiac Device-Related Infections: An Update

IE is a deadly disease requiring prompt diagnosis for adequate patient's management. The diagnosis requires the integration of clinical signs, microbiology data and imaging data and proper discussion within a multidisciplinary team, the endocarditis team. Since the introduction of ¹⁸F-FDG-PET/CT and WBC SPECT/CT in the diagnostic algorithm of PVE the nuclear medicine imaging specialists is active part of the Endocarditis Team, requiring proper knowledge of dedicated imaging acquisition protocols, expertise for imaging reading and interpretations to select the best test or combination of tests for each specific clinical situation. In this manuscript, we will review the main technical aspects of each imaging procedure, the most recent literature with specific regards to special challenging populations and provide clinical examples.

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 detection of infectious endocarditis may be enhanced by a repeat FDG-PET while maintaining patients on a ketogenic diet

BACKGROUND

This study aims to determine whether the suppression of myocardial FDG uptake and detection of infectious endocarditis (IE) may be enhanced when FDG-PET is repeated on the next day while maintaining patients on a ketogenic diet in the interim.

METHODS

Seventeen patients with definite IE underwent FDG-PET investigations both after a conventional metabolic preparation (> 12-hour fast after a low-carbohydrate evening meal) and a subsequent 12-hour extension of the low-carbohydrate diet followed by an additional > 12-hour fast.

RESULTS

Plasma biomarkers showed increased ketogenic metabolism between the two FDG-PET scans. A myocardial FDG uptake persisted on the 1st PET in 9 patients (53%) for whom myocardial FDG uptake decreased significantly on the 2nd PET (SUVmax: 6.05 ± 3.25 vs 4.32 ± 3.47, P = 0.021), resulting in an enhancement in the diagnostic confidence of IE in 6 cases. These enhancements were not documented in the 8 patients exhibiting a total suppression of myocardial FDG uptake on the 1st PET.

CONCLUSIONS

Better suppression of myocardial uptake and enhanced detection of IE may be achieved when an FDG-PET, showing an incomplete suppression of the myocardial FDG uptake, is repeated as soon as the next day, while maintaining patients on a ketogenic diet in the interim.

Value of 18F-FDG pet/CT for prognostic assessment in patients with infective endocarditis

BACKGROUND

¹⁸F-FDG PET/CT is a valuable diagnostic tool in infective endocarditis (IE). However, the prognostic value is unclear. This study aims to evaluate the prognostic performance of ¹⁸F-FDG PET/CT in native valve endocarditis (NVE) and prosthetic valve endocarditis (PVE).

METHODS

We retrospectively included 76 patients treated for definite IE (NVE and PVE) that underwent ¹⁸F-FDG PET/CT between January 2016 and December 2018. Clinical, echocardiographic and ¹⁸F-FDG PET/CT (pathologic valvular ¹⁸F-FDG uptake, extracardiac complications (ECC)) data were collected. The primary endpoint was defined as mortality or recurrence of IE at a one-year follow-up.

RESULTS

Pathologic valvular ¹⁸F-FDG uptake was detected in 32 of 57 (56.1%) patients, 30% (9/30) in NVE and 85.2% (23/27) in PVE group. Atrial fibrillation (OR 3.90, 95% CI = 1.14-16.3), prior anticoagulation treatment (OR 6.37, 95% CI = 1.89-26.7), large vegetation (≥ 10 mm) (OR 4.05, 95% CI = 1.14-16.1), perivalvular complications (OR 7.22, 95% CI = 1.68-55.1) and abscess (OR 10.9, 95% CI = 1.84-283) were associated with positive PET/CT. Extracardiac complications were found in 27 of 76 (35.5%) patients, 42.9% (18/42) in the NVE and 26.5% (9/34) in the PVE group. Pathological valvular tracer uptake (HR 1.20, 95% CI = 0.43-3.37) or extracardiac complications (HR 0.58, 95% CI = 0.21-1.62) were not associated with the occurrence of the primary endpoint.

CONCLUSION

Our study could not demonstrate a prognostic value of ¹⁸F-FDG PET/CT in IE, but confirms high diagnostic performance, which may compromise prognostic significance by accelerated optimal treatment because of earlier diagnostic certainty.

[18F]-Fludeoxyglucose Positron Emission Tomography/Computed Tomography with Radiomics Analysis in Patients Undergoing Aortic In-Situ Reconstruction with Cryopreserved Allografts

BACKGROUND

The aim of this study was to evaluate the effectiveness of positron emission tomography/computed tomography with [¹⁸F]-fludeoxyglucose (FDG-PET/CT) and radiomics analysis in detecting differences between the native aorta and the abdominal aortic allograft after the total eradication of infection in patients undergoing infected graft removal and in situ reconstruction with cryopreserved allografts.

METHODS

Between January 2008 and December 2018, 56 vascular reconstructions with allografts have been performed at our department. The present series included 12 patients undergoing abdominal aortic in situ reconstruction with cryopreserved allografts. During the follow-up, all patients underwent a total-body [¹⁸F]FDG PET/CT with subsequent radiomics analysis. In all patients, a comparative analysis between the data extracted from native aorta and cryopreserved graft for each patient was performed.

RESULTS

All patients were male with a mean age of 72.8 years (range 63-84). Mean duration of follow-up was 51.3 months (range 3-120). During the follow-up, 2 patients (16.7%) needed a redo allograft-related surgical intervention. Overall, the rate of allograft dilatation was 33.3%. No patient had a redo infection during the follow-up. Radiomics analysis showed a different signature of implanted allograft and native aorta. Comparative analysis between the native aortas and cryopreserved allografts (dilated or not) showed several statistical differences for many texture features.

CONCLUSIONS

The higher metabolic activity of allografts could indicate a state of immune-mediated degeneration. This theory should be proven with prospective, multicentric studies with larger sample sizes.

Prevention and Management of Cardiac Implantable Electronic Device Infections: State-of-the-Art and Future Directions

Cardiac implantable electronic device (CIED) infection is an increasingly common complication of device therapy. CIED infection confers significant patient morbidity and health care expenditure, hence it is essential that clinicians recognise the contemporary strategies for predicting, reducing and treating these events. Recent technological advances-in particular, the development of antimicrobial envelopes, leadless devices and validated risk scores-present decision-makers with novel strategies for managing this expanding patient population. This review summarises the key issues facing CIED patients and their physicians, and explores the supporting evidence for the latest therapeutic developments in this field.

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.

Accuracy of 18F-FDG PET/CT in patients with the suspicion of cardiac implantable electronic device infections

BACKGROUND

Utility of 18F-FDG PET/CT in diagnosing infective endocarditis (IE) associated with cardiac implantable electronic devices (CIEDs) is not well established. Current ESC guidelines recommend the use of FDG-PET imaging in patients with CIEDs and positive blood cultures, but the number of studies evaluating the diagnostic performance of FDG-PET imaging in these patients remain limited. Our objective was to assess the diagnostic yield of 18F-FDG PET/CT in patients with suspected CIED infections, differentiating between pocket infection (PI) and lead infection (CIED-IE).

METHODS AND RESULTS

From 2013 to 2018, all patients (n = 63) admitted to a hospital with suspected CIED infection were prospectively recruited, undergoing a diagnostic work-up including a PET/CT. Explanted devices and material from the pocket were cultured. 14 cases corresponded to isolated PI and 13 were categorized as CIED-IE. Considering radionuclide uptake in the intracardiac portion of the lead, sensitivity and specificity of PET/CT for CIED-IE were 38.5% and 98.0%, respectively. Positive (19.2) and negative (0.6) likelihood ratio values, suggest that a positive PET/CT is much more probable to correspond to a patient with CIED-IE, whereas it is not possible to exclude this diagnosis when negative. For PI, sensitivity and specificity were 72.2% and 95.6%, respectively.

CONCLUSIONS

The yield of 18F-FDG PET/CT for suspected CIED infections differs depending on the site of infection. Due to very high specificity but poor sensitivity, negative studies must be interpreted with caution if the suspicion of CIED-IE is high.

The valve uptake index: improving assessment of prosthetic valve endocarditis and updating [18F]FDG PET/CT(A) imaging criteria

Aims

Diagnosis of prosthetic valve endocarditis (PVE) by positron emission computed tomography angiography (PET/CTA) is based on visual and quantitative morpho-metabolic features. However, the fluorodeoxyglucose (FDG) uptake pattern can be sometimes visually unclear and susceptible to subjectivity. This study aimed to validate a new parameter, the valve uptake index [VUI, maximum standardized uptake value (SUVmax)−mean standardized uptake value (SUVmean)/SUVmax], designed to provide a more objective indication of the distribution of metabolic activity. Secondly, to re-evaluate the utility of traditionally used PVE imaging criteria and determine the potential value of adding the VUI in the diagnostic algorithm of PVE.

Methods and results

Retrospective analysis of 122 patients (135 prosthetic valves) admitted for suspicion of endocarditis, with a conclusive diagnosis of definite (N = 57) or rejected (N = 65) PVE, and who had undergone a cardiac PET/CTA scan as part of the diagnostic evaluation. We measured the VUI and recorded the SUVmax, SUVratio, uptake pattern, and the presence of endocarditis-related anatomic lesions. The VUI, SUVmax, and SUVratio values were 0.54 ± 0.1 vs. 0.36 ± 0.08, 7.68 ± 3.07 vs. 3.72 ± 1.11, and 4.28 ± 1.93 vs. 2.16 ± 0.95 in the ‘definite’ PVE group vs. the ‘rejected’ group, respectively (mean ± SD; P < 0.001). A cut-off value of VUI > 0.45 showed a sensitivity, specificity, and diagnostic accuracy for PVE of 85%, 88%, and 86.7% and increased diagnostic ability for confirming endocarditis when combined with the standard diagnostic criteria.

Conclusions

The VUI demonstrated good diagnostic accuracy for PVE, even increasing the diagnostic power of the traditionally used morphometabolic parameters, which also confirmed their own diagnostic performance. More research is needed to assess whether the integration of the VUI into the PVE diagnostic algorithm may clarify doubtful cases and thus improve the diagnostic yield of PET/CTA.

Staphylococcus Aureus Infective Endocarditis: JACC Patient Pathways

A 19-year-old female patient presented with Staphylococcus aureus infective endocarditis, with suspected subdural brain hemorrhage, disseminated intravascular coagulopathy, and septic renal as well as spleen infarcts. The patient had extensive vegetations on the mitral and tricuspid valves and underwent urgent mitral and tricuspid repair. This paper discusses the clinical case and current evidence regarding the management and treatment of Staphylococcus aureus endocarditis.

Nuclear Imaging in Infective Endocarditis

Infective endocarditis (IE) is a life-threatening disease with stable prevalence despite prophylactic, diagnostic, and therapeutic advances. In parallel to the growing number of cardiac devices implanted, the number of patients developing IE on prosthetic valves and cardiac implanted electronic device (CIED) is increasing at a rapid pace. The diagnosis of IE is particularly challenging, and currently relies on the Duke-Li modified classification, which include clinical, microbiological, and imaging criteria. While echocardiography remains the first line imaging technique, especially in native valve endocarditis, the incremental value of two nuclear imaging techniques, ¹⁸F-fluorodeoxyglucose positron emission tomography with computed tomography (¹⁸F-FDG-PET/CT) and white blood cells single photon emission tomography with computed tomography (WBC-SPECT), has emerged for the management of prosthetic valve and CIED IE. In this review, we will summarize the procedures for image acquisition, discuss the role of ¹⁸F-FDG-PET/CT and WBC-SPECT imaging in different clinical situations of IE, and review the respective diagnostic performance of these nuclear imaging techniques and their integration into the diagnostic algorithm for patients with a suspicion of IE.

Role of Multimodal Imaging in Patients With Suspected Infections After the Bentall Procedure

Purpose: This study aimed to assess the diagnostic performances of multimodal imaging [i.e., white blood cell single-photon emission computed tomography/CT (^99mTc-HMPAO-WBC SPECT/CT) and 18-fluoride-fluorodeoxyglucose positron emission tomography/CT ([¹⁸F]FDG PET/CT)] in patients with suspected infection after the Bentall procedure, proposing new specific diagnostic criteria for the diagnosis.

Methods: Between January 2009 and December 2019, we selected within a cardiovascular infections registry, 76 surgically treated patients (27 women and 49 men, median 66 years, and range 29–83 years). All the patients underwent molecular imaging for a suspected infection after the replacement of the aortic valve and ascending aorta according to the Bentall procedure. We analyzed 98 scans including 49 ^99mTc-WBC and 49 [¹⁸F]FDG PET/CT. A total of 22 patients with very early/early suspected infection (<3 months after surgery) were imaged with both the techniques. Positive imaging was classified according to the anatomical site of increased uptake: to the aortic valve (AV), to both the AV and AV tube graft (AVTG) or to the TG, to surrounding tissue, and/or to extracardiac sites (embolic events or other sites of concomitant infection). Standard clinical workup included in all the patients having echocardiography/CT, blood culture, and the Duke criteria. Pretest probability and positive/negative likelihood ratio were calculated. Sensitivity and specificity of ^99mTc labeled hexamethylpropylene amine oxime-WBC SPECT/CT (^99mTc-HMPAO-WBC SPECT/CT) and [¹⁸F]FDG PET/CT imaging were calculated by using microbiology (n = 35) or clinical follow-up (n = 41) as final diagnosis. ^99mTc-HMPAO-WBC scintigraphy and [¹⁸F]FDG PET/CT findings were compared with 95% CIs by using the McNemar test to those of echocardiography/CT, blood culture, and the Duke criteria.

Results: Sensitivity, specificity, and accuracy of ^99mTc-HMPAO-WBC were 86, 92, and 88%, respectively, with a slightly higher sensitivity for tube graft infection (TGI) as compared to isolated AV and combined AVTG. Overall, sensitivity, specificity, and accuracy of [¹⁸F]FDG PET/CT were 97, 73, and 90%, respectively. In 22 patients with suspected very early and early postsurgical infections, the two imaging modalities were concordant in 17 cases [10 true positive (TP) and 7 true negative (TN)]. [¹⁸F]FDG PET/CT presented a higher sensitivity than ^99mTc-HMPAO-WBC scan. ^99mTc-HMPAO-WBC scan correctly classified as negative three false-positive (FP) PET/CT findings.

Conclusion: Our findings supported the use of ^99mTc-HMPAO-WBC SPECT/CT and [¹⁸F]FDG PET/CT in patients with suspicion infection after the Bentall procedure early in the course of the disease onset to confirm the diagnosis and provide a comprehensive assessment of disease burden through the proposed criteria.

Hypermetabolism of the spleen or bone marrow is an additional albeit indirect sign of infective endocarditis at FDG-PET

PURPOSE

This study aimed at determining the diagnostic implications of indirect signs of infection at FDG-PET-i.e., hypermetabolisms of the spleen and/or bone marrow (HSBM)-when documented in patients with known or suspected infective endocarditis (IE).

METHODS

HSBM were defined by higher mean standardized uptake values comparatively to that of the liver on FDG-PET images from patients with a high likelihood of IE and prospectively included in a multicenter study.

RESULTS

Among the 129 included patients, IE was ultimately deemed as definite in 88 cases. HSBM was a predictor of definite IE (P = 0.014; odds ratio (OR) 3.2), independently of the criterion of an abnormal cardiac FDG uptake (P = 0.0007; OR 9.68), and a definite IE was documented in 97% (29/30) of patients showing both HSBM and abnormal cardiac uptake, 78% (7/9) of patients with only abnormal cardiac uptake, 67% (42/63) of patients with only HSBM, and 37% (10/27) of patients with neither one.

CONCLUSION

In this cohort with a high likelihood of IE, HSBM is an additional albeit indirect sign of IE, independently of the criterion of an abnormal cardiac uptake, and could reinforce the suspicion of IE in the absence of any other infectious, inflammatory, or malignant disease.

Staphylococcus Aureus Infective Endocarditis: JACC Patient Pathways

A 19-year-old female patient presented with Staphylococcus aureus infective endocarditis, with suspected subdural brain hemorrhage, disseminated intravascular coagulopathy, and septic renal as well as spleen infarcts. The patient had extensive vegetations on the mitral and tricuspid valves and underwent urgent mitral and tricuspid repair. This paper discusses the clinical case and current evidence regarding the management and treatment of Staphylococcus aureus endocarditis.

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.

18F-FDG PET/CT in cardiovascular infection and inflammation

The diagnosis of cardiovascular infection and inflammation by [¹⁸F]FDG PET/CT in Nuclear Cardiology is of growing interest, because with respect to echocardiography this technique has improved the certainty in the diagnosis of infective endocarditis in patients with prosthetic valves, the increasing number of patients with implantable cardiac devices because of the progressive ageing of the population, as well as in patients with suspected large vessel vasculitis. All are serious clinical situations which require correct diagnosis and appropriate treatment as soon as possible, because they can cause severe complications, high mortality and also increased health care costs. We review the use of [¹⁸F]FDG PET/CT in cardiovascular infection and inflammation, including the clinical point of view and the contribution of other image modalities. We focus on the appropriate methodology for this exploration, patient preparation, image acquisition and correct interpretation and the quantification possibilities, defining the specific characteristics of the diagnosis in patients with prosthetic valves, implantable cardiac devices and large vessel vasculitis in the initial diagnosis as well as during follow-up to assess treatment response. We analyze the possible causes of false positive and false negative results and emphasize the special value of a multidisciplinary team for optimal management of these patients.

[18F] FDG PET/CT can improve the diagnostic accuracy for aortic endograft infection

PURPOSE

Aortic endograft infection (EI) can result in potentially life-threatening vascular complications. Unfortunately, it is difficult to obtain a correct diagnosis at an early stage in many patients. This report aims at validating the use of [¹⁸F] FDG PET/CT imaging for suspected endograft infections in a prospectively collected cohort of patients treated with EVAR and TEVAR.

MATERIALS AND METHODS

During a 14-year period, 366 patients required aortic stent graft. All procedures were performed electively, except for one patient. Among these 366 patients, eleven patients (3%) were suspected to have aortic EI. Contrast-enhanced CT and FDG PET/CT were performed in all 11 patients. Medical charts and imaging were analysed for these 11 cases, with initial positive CT.

RESULTS

The final diagnosis of EI was established in seven (1,9%) based on clinical features, laboratory investigations and a significant [¹⁸F] FDG uptake in the aortic graft as well as the aortic wall. The median time from the initial EVAR/TEVAR to diagnosed infection was 180 days. During follow-up, the seven patients had a second PET/CT that was compared with the initial evaluation, decreased uptake was correlated with clinical improvement.

CONCLUSIONS

Contemporary diagnostic imaging for a potentially lethal endograft infection lacks precision, this observational study illustrates the potential clinical value of [¹⁸F] FDG PET/CT in the management of aortic EI. [¹⁸F] FDG PET/CT constitutes an imaging modality able to confirm the diagnosis, monitor disease progression as well as the effect of pharmaceutical treatment and detect relapse.