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

The [99mTc]Tc-HMPAO-labelled white blood cell SPECT/CT as a novel criterion for infective endocarditis diagnosis

AIMS

Infective endocarditis (IE) poses a significant clinical challenge, necessitating nuanced diagnostic tools for early and accurate detection. The diagnostic role of the hybrid technique of single-photon emission tomography-computed tomography with technetium-99 m-hexamethylpropyleneamine oxime-labelled leukocytes ([99mTc]Tc-HMPAO-SPECT/CT) has evolved in recent years. This single-center study assessed whether the recent inclusion in the 2023 European Society of Cardiology modified diagnostic criteria of IE (2023 ESC) of infectious lesions detected with [99mTc]Tc-HMPAO-SPECT/CT affects their diagnostic performance.

METHODS AND RESULTS

Between 2015 and 2019, we enrolled 205 consecutive adults with suspected IE. All participants underwent [99mTc]Tc-HMPAO-SPECT/CT scans (370-740 MBq). Scans were deemed positive in the presence of intracardiac abnormal tracer uptake and/or within the cardiac implantable electronic device. Patients were prospectively followed-up for 12 ± 10 months. Local device infection (LDI) or IE was diagnosed in 75 (36.6 %) patients, while 72 (35.1 %) [99mTc]Tc-HMPAO-SPECT/CT results returned positive. Moreover, extracardiac infectious foci were detected in 25 % of [99mTc]Tc-HMPAO-SPECT/CT scans. The inclusion of both intracardiac and extracardiac lesions detected with [99mTc]Tc-HMPAO-SPECT/CT yields significantly higher sensitivity (p = 0.003) and negative predictive value (NPV) (p = 0.009).

CONCLUSION

The inclusion of [99mTc]Tc-HMPAO-SPECT/CT into the IE diagnostic work-up improves the appropriate classification of patients. For patients with IE, the extended inclusion of lesions detected with [99mTc]Tc-HMPAO-SPECT/CT in the ESC 2023 diagnostic criteria significantly improves sensitivity and NPV while reducing potential IE misdiagnoses. This pioneering imaging modality is poised to become an integral component of clinical practice, promising to advance IE diagnosis and management.

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.

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.

Dual-Time-Point 18F-FDG PET/CT in Infective Endocarditis: Impact of Delayed Imaging in the Definitive Diagnosis of Endocarditis

Infective endocarditis (IE) is a major public health condition due to the associated high morbidity and mortality. Our objective was to evaluate the utility of dual-time 2-deoxy-2-[18F] fluoro-D-glucose (18F-FDG) Positron Emission Tomography/Computed Tomography (PET/CT) imaging in the diagnosis of active IE in patients with suspected native valve endocarditis (NVE) and prosthetic valve endocarditis (PVE). For this purpose, a retrospective study was carried out, including patients suspicious of NVE or PVE who underwent a dual-time-point 18F-FDG PET/CT. A final diagnosis was established by the Endocarditis Team after patient follow-up using all the available findings. Sixty-nine patients were assessed. A final diagnosis of NVE was established in 3 patients of the 34 by 18F-FDG PET/CT and in the case of PVE was established in 20 patients of the 35. A statistically significant association was found when evaluating the association between PET diagnosis at early acquisition and final diagnosis of IE (χ2 = 30.198, p < 0.001) and PET diagnosis at delayed acquisition for final diagnosis of IE (χ2 = 9.412, p = 0.002). Delayed PET/CT imaging determined the IE diagnosis in 16/58 of the studies. In conclusion, delayed 18F-FDG PET/CT imaging seems to be useful in improving the definitive diagnosis of 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.

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.

Prognosis and follow-up of patients with prosthetic valve endocarditis treated conservatively in relation to WBC-SPECT imaging

BACKGROUND

Our objective was to evaluate in patients with prosthetic valve endocarditis (PVE) treated conservatively, the prognostic value of white blood cell (WBC) signal intensity on SPECT and to describe the evolution of the WBC signal under antibiotics.

METHODS

Patients with PVE treated conservatively and positive WBC-SPECT imaging were identified retrospectively. Signal intensity was classified as intense if equal to or higher, or mild if lower, than the liver signal. Clinical, biological, imaging and follow-up information were collected from medical files.

RESULTS

Among 47 patients, WBC signal was classified as intense in 10 patients and as mild, in 37. The incidence of the primary composite endpoint (death, late cardiac surgery, or relapse) was significantly higher in patients with intense vs. mild signal (90% vs. 11%). Twenty-five patients underwent a second WBC-SPECT imaging during follow-up. The prevalence of WBC signal decreased progressively from 89% between 3 and 6 weeks to 42% between 6 and 9 weeks and 8% more than 9 weeks after initiation of antibiotics.

CONCLUSIONS

In patients with PVE treated conservatively, intense WBC signal was associated with poor outcome. WBC-SPECT imaging appears as an interesting tool for risk stratification and to monitor locally the efficacy of antibiotic treatment.

Absence of infective endocarditis relapse when end-of-treatment fluorodeoxyglucose positron emission tomography/computed tomography is negative

AIMS

In non-operated infective endocarditis (IE), relapse may impair the outcome of the disease. The aim of the study was to evaluate the relationship between end-of-treatment (EOT) fluorodeoxyglucose positron emission tomography/computed tomography FDG-PET/CT results and relapse in non-operated IE either on native or prosthetic valve.

METHODS AND RESULTS

We included 62 patients who underwent an EOT FDG-PET/CT for non-operated IE performed between 30 and 180 days of antibiotic therapy initiation. Qualitative valve assessment categorized initial and EOT FDG-PET/CT as negative or positive. Quantitative analyses were also conducted. Clinical data from medical charts were collected, including endocarditis team decision for IE diagnosis and relapse. Forty-one (66%) patients were male with a median age of 68 years (57; 80) and 42 (68%) had prosthetic valve IE. End-of-treatment FDG-PET/CT was negative in 29 and positive in 33 patients. The proportion of positive scans decreased significantly compared with initial FDG-PET/CT (53% vs. 77%, respectively, P < 0.0001). All relapses (n = 7, 11%) occurred in patients with a positive EOT FDG-PET/CT with a median delay after EOT FDG-PET/CT of 10 days (0; 45). The relapse rate was significantly lower in negative (0/29) than in positive (7/33) EOT FDG-PET/CT (P = 0.01).

CONCLUSION

In this series of 62 patients with non-operated IE who underwent EOT FDG-PET/CT, those with a negative scan (almost half of the study population) did not develop IE relapse after a median follow-up of 10 months. These findings need to be confirmed by prospective and larger studies.

Candida endocarditis: Update on management considerations

The rise in incidence rates of invasive candidiasis warrants an increase in attention and efforts toward preventing and treating this virulent infection. Cardiac involvement is one of the most feared sequelae and has a poor prognosis. Despite the introduction of several novel antifungal agents over the past quarter century, complications and mortality rates due to Candida endocarditis have remained high. Although fungal endocarditis has a mechanism similar to bacterial endocarditis, no specific diagnostic criteria or algorithm exists to help guide its management. Furthermore, recent data has questioned the current guidelines recommending a combined approach of antifungal agents with surgical valve or indwelling prostheses removal. With the emergence of multidrug-resistant Candida auris, a focus on improved prophylactic measures and management strategies is necessary.

[Positron emission tomography in cardiological practice]

The utility of positron emission tomography in cardiology currently goes beyond the ischemic heart disease and covers an increasingly wider range of non-coronary pathology, which requires timely expert diagnostics, including chronic heart disease of any etiology, valvular and electrophysiology disorders, cardiooncology. Authors emphasize the importance of the development of positron emission tomography technologies in the Russian Federation. This includes the development and implementation of new radiopharmaceuticals for the diagnosis of pathological processes of the cardiovascular system, systemic and local inflammation, including atherosclerosis, impaired perfusion and myocardial metabolism, and also for solving specific diagnostic tasks in comorbid pathology.

Contemporary Features and Management of Endocarditis

Infective endocarditis is a rare but devastating disease. Morbidity and mortality rates have failed to improve despite new technological advances. The disease has evolved over time with new significant populations at risk-most notably those with prosthetic valves or implantable cardiovascular devices. These devices pose new challenges for achieving a timely and accurate diagnosis of infection. While the modified Duke criteria is accepted as the gold standard for diagnosing native valve endocarditis, it has been shown to have significantly inferior sensitivity when it comes to identifying infections related to right-heart endocarditis, prosthetic valves, and indwelling cardiac devices. Additionally, prosthetic valves and cardiovascular implantable electronic devices can exhibit shadowing and artifact, rendering transthoracic echocardiography and transesophageal echocardiography results inconclusive or even normal. Having a keen awareness of the varying clinical presentations, as well as emerging valvular imaging modalities such as F-fluorodeoxyglucose cardiac positron-emission tomography plus computed tomography, promises to improve the evaluation and diagnosis of infective endocarditis. However, indications for appropriate use of these studies and guidance on modern clinical management are still needed.

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.

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.

Contemporary Review of Multi-Modality Cardiac Imaging Evaluation of Infective Endocarditis

Infective endocarditis (IE) remains to be a heterogeneous disease with high morbidity and mortality rates, which can affect native valves, prosthetic valves, and intra-cardiac devices, in addition to causing systemic complications. The combination of clinical, laboratory, and cardiac imaging evaluation is critical for early diagnosis and risk stratification of IE. This can facilitate timely medical and surgical management to improve patient outcomes. Key imaging findings for IE include vegetations, valve perforation, prosthetic valve dehiscence, pseudoaneurysms, abscesses, and fistulae. Transthoracic echocardiography continues to be the first-line imaging modality of choice, while transesophageal echocardiography subsequently provides an improved structural assessment and characterization of lesions to facilitate management decision in IE. Recent advances in other imaging modalities, especially cardiac computed tomography and 18F-fluorodeox-yglucose positron emission tomography, and to a lesser extent cardiac magnetic resonance imaging and other nuclear imaging techniques, have demonstrated important roles in providing complementary IE diagnostic and prognostic information. This review aims to discuss the individual and integrated utilities of contemporary multi-modality cardiac imaging for the assessment and treatment guidance of IE.

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.

To what extent does prior antimicrobial therapy affect the diagnostic performance of radiolabeled leukocyte scintigraphy in infective endocarditis?

AIMS

This prospective, single-center study sought to assess to what extent there is interference between the hybrid technique of single-photon emission tomography-computed tomography with technetium99m-hexamethylpropyleneamine oxime-labeled leukocytes (99mTc-HMPAO-SPECT/CT) and antimicrobial therapy in patients with infective endocarditis (IE).

METHODS AND RESULTS

During the years 2015-2019, we enrolled 205 consecutive adults with suspected IE, all underwent 99mTc-HMPAO-SPECT/CT. The study population was divided into those who had received antimicrobial therapy up to 30 days prior to 99mTc-HMPAO-SPECT/CT (group 1, n = 96) and those who had not (group 2, n = 109). Patients were prospectively observed for 12 ± 10 months. Group 1 presented higher positive predictive values (91.89% vs. 60.00%, = 0.001), and decreased negative predictive values (77.97% vs. 90.54%, P = 0.04). Patients treated with antimicrobial therapy displayed false-negative 99mTc-HMPAO-SPECT/CT results more often [odds ratio (OR), 4.63; 95% confidence interval (CI), 1.41-15.23, P = .01], particularly when intravenous (OR 5.37; 95% CI 1.73-16.62, P = .004), definite (OR 9.43; 95% CI 2.65-33.51, P = .001), and combination antibiotic regimens (OR 8.1; 95% CI 2.57-25.64, P = .001) had been administered.

CONCLUSION

Prior antibiotic therapy affects 99mTc-HMPAO-SPECT/CT diagnostic properties. Patients treated with antimicrobial therapy display false-negative 99mTc-HMPAO-SPECT/CT results more often, especially if intravenous, definite, or combination regimens are administered.

Current Views on Infective Endocarditis: Changing Epidemiology, Improving Diagnostic Tools and Centering the Patient for Up-to-Date Management

Infective endocarditis (IE) is a rare but potentially life-threatening disease, sometimes with longstanding sequels among surviving patients. The population at high risk of IE is represented by patients with underlying structural heart disease and/or intravascular prosthetic material. Taking into account the increasing number of intravascular and intracardiac procedures associated with device implantation, the number of patients at risk is growing too. If bacteremia develops, infected vegetation on the native/prosthetic valve or any intracardiac/intravascular device may occur as the final result of invading microorganisms/host immune system interaction. In the case of IE suspicion, all efforts must be focused on the diagnosis as IE can spread to almost any organ in the body. Unfortunately, the diagnosis of IE might be difficult and require a combination of clinical examination, microbiological assessment and echocardiographic evaluation. There is a need of novel microbiological and imaging techniques, especially in cases of blood culture-negative. In the last few years, the management of IE has changed. A multidisciplinary care team, including experts in infectious diseases, cardiology and cardiac surgery, namely, the Endocarditis Team, is highly recommended by the current guidelines.

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.

Nuclear Methods for Immune Cell Imaging: Bridging Molecular Imaging and Individualized Medicine

Inflammation is a key mechanistic contributor to the progression of cardiovascular disease, from atherosclerosis through ischemic injury and overt heart failure. Recent evidence has identified specific roles of immune cell subpopulations in cardiac pathogenesis that diverges between individual patients. Nuclear imaging approaches facilitate noninvasive and serial quantification of inflammation severity, offering the opportunity to predict eventual outcome, stratify patient risk, and guide novel targeted molecular therapies against specific leukocyte subpopulations. Here, we will discuss the established and emerging nuclear imaging methods to label and track exogenous and endogenous immune cells, with a particular focus on clinical situations in which targeted molecular inflammation imaging would be advantageous. The expanding options for imaging inflammation provide the foundation to bridge between molecular imaging and individual therapy.

Outcomes in cardiac implantable electronic device-related infective endocarditis: a systematic review of current literature

Aim: Cardiac implantable electronic device infective endocarditis is a serious infection with poor prognosis. Materials & methods: The systematic review of the literature was conducted using searches from the various databases. We included studies published between January 2010 and June 2021. Results: A total of 35 articles met the inclusion criteria. Patients were approximately 70 years old and an average of 71.2% of patients were male. The most common presenting feature was a fever. The modified Duke criteria was used to aid diagnosis. Management entailed extraction of the cardiac implantable electronic device in 80.5% of the studies. The overall mortality rates ranged from 4 to 36%. The most frequently isolated organism was Staphylococcus aureus. Conclusion: Cardiac implantable electronic device infective endocarditis needs timely diagnosis and effective management for promising outcomes.

Native valve, prosthetic valve, and cardiac device-related infective endocarditis: A review and update on current innovative diagnostic and therapeutic strategies

Infective endocarditis (IE) is a life-threatening microbial infection of native and prosthetic heart valves, endocardial surface, and/or indwelling cardiac device. Prevalence of IE is increasing and mortality has not significantly improved despite technological advances. This review provides an updated overview using recent literature on the clinical presentation, diagnosis, imaging, causative pathogens, treatment, and outcomes in native valve, prosthetic valve, and cardiac device-related IE. In addition, the experimental approaches used in IE research to improve the understanding of disease mechanisms and the current diagnostic pipelines are discussed, as well as potential innovative diagnostic and therapeutic strategies. This will ultimately help towards deriving better diagnostic tools and treatments to improve IE patient outcomes.

18F-FDG PET/CT improves diagnostic certainty in native and prosthetic valve Infective Endocarditis over the modified Duke Criteria

BACKGROUND

International guidance recognizes the shortcomings of the modified Duke Criteria (mDC) in diagnosing infective endocarditis (IE) when transoesophageal echocardiography (TOE) is equivocal. 18F-FDG PET/CT (PET) has proven benefit in prosthetic valve endocarditis (PVE), but is restricted to extracardiac manifestations in native disease (NVE). We investigated the incremental benefit of PET over the mDC in NVE.

METHODS

Dual-center retrospective study (2010-2018) of patients undergoing myocardial suppression PET for NVE and PVE. Cases were classified by mDC pre- and post-PET, and evaluated against discharge diagnosis. Receiver Operating Characteristic (ROC) analysis and net reclassification index (NRI) assessed diagnostic performance. Valve standardized uptake value (SUV) was recorded.

RESULTS

69/88 PET studies were evaluated across 668 patients. At discharge, 20/32 had confirmed NVE, 22/37 PVE, and 19/69 patients required surgery. PET accurately re-classified patients from possible, to definite or rejected (NRI: NVE 0.89; PVE 0.90), with significant incremental benefit in both NVE (AUC 0.883 vs 0.750) and PVE (0.877 vs 0.633). Sensitivity and specificity were 75% and 92% in NVE; 87% and 86% in PVE. Duration of antibiotics and C-reactive Protein level did not impact performance. No diagnostic SUV cut-off was identified.

CONCLUSION

PET improves diagnostic certainty when combined with mDC in NVE and PVE.

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.

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.

Best Practices for Imaging Cardiac Device-Related Infections and Endocarditis: A JACC: Cardiovascular Imaging Expert Panel Statement

The diagnosis of cardiac device infection and, more importantly, accurate localization of the infection site, such as defibrillator pocket, pacemaker lead, along the peripheral driveline or central portion of the left ventricular assist device, prosthetic valve ring abscesses, and perivalvular extensions, remain clinically challenging. Although transthoracic and transesophageal echocardiography are the first-line imaging tests in suspected endocarditis and for assessing hemodynamic complications, recent studies suggest that cardiac computed tomography (CT) or CT angiography and functional imaging with ¹⁸F-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) with CT (FDG PET/CT) may have an incremental role in technically limited or inconclusive cases on echocardiography. One of the key benefits of FDG PET/CT is in its detection of inflammatory cells early in the infection process, before morphological damages ensue. However, there are many unanswered questions in the literature. In this document, we provide consensus on best practices among the various imaging studies, which includes the detection of cardiac device infection, differentiation of infection from inflammation, image-guided patient management, and detailed recommendations on patient preparation, image acquisition, processing, interpretation, and standardized reporting.

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.

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.

The year in cardiology: imaging

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Advantages of 18F-FDG PET/CT Imaging over Modified Duke Criteria and Clinical Presumption in Patients with Challenging Suspicion of Infective Endocarditis

According to European Society of Cardiology guidelines (ESC2015) for infective endocarditis (IE) management, modified Duke criteria (mDC) are implemented with a degree of clinical suspicion degree, leading to grades such as "possible" or "rejected" IE despite a persisting high level of clinical suspicion. Herein, we evaluate the ¹⁸F-FDG PET/CT diagnostic and therapeutic impact in IE suspicion, with emphasis on possible/rejected IE with a high clinical suspicion. Excluding cases of definite IE diagnosis, 53 patients who underwent ¹⁸F-FDG PET/CT for IE suspicion were selected and afterwards classified according to both mDC (possible IE/Duke 1, rejected IE/Duke 0) and clinical suspicion degree (high and low IE suspicion). The final status regarding IE diagnosis (gold standard) was based on the multidisciplinary decision of the Endocarditis Team, including the 'imaging specialist'. PET/CT images of the cardiac area were qualitatively interpreted and the intensity of each focus of extra-physiologic ¹⁸F-FDG uptake was evaluated by a maximum standardized uptake value (SUVmax) measurement. Extra-cardiac ¹⁸F-FDG PET/CT pathological findings were considered to be a possible embolic event, a possible source of IE, or even a concomitant infection. Based on the Endocarditis Team consensus, final diagnosis of IE was retained in 19 (36%) patients and excluded in 34 (64%). With a sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and global accuracy of 79%, 100%, 100%, 89%, and 92%, respectively, PET/CT performed significantly better than mDC (p = 0.003), clinical suspicion degree (p = 0.001), and a combination of both (p = 0.001) for IE diagnosis. In 41 patients with possible/rejected IE but high clinical suspicion, sensitivity, specificity, PPV, NPV, and global accuracies were 78%, 100%, 100%, 85%, and 90%, respectively. Moreover, PET/CT contributed to patient management in 24 out of 53 (45%) cases. ¹⁸F-FDG PET/CT represents a valuable diagnostic tool that could be proposed for challenging IE cases with significant differences between mDC and clinical suspicion degree. ¹⁸F-FDG PET/CT allows a binary diagnosis (definite or rejected IE) by removing uncertain diagnostic situations, thus improving patient therapeutic management.

Diagnosis and Image-guided Therapy of Cardiac Left Ventricular Assist Device Infections

Due to limited availability of donor hearts, more and more end stage heart failure patients are dependent on left ventricular assist device (LVAD) as their destination therapy rather than the original intended use as a bridge for heart transplantation. While LVADs improve life expectancy in these patients, infection emerges as one of the major adverse events. Early and accurate localization of LVAD infection is critical, as it can significantly influence clinical management decisions and ultimately impact patient outcome. Although the International Society of Heart and Lung Transplantation has defined 3 categories for LVAD infection: (1) LVAD-specific infection, (2) LVAD-related infection, and (3) non-LVAD infection, there is still lack of standardized criteria for diagnosing these 3 types of LVAD infections. Morphologically based imaging tools such as transesophageal echocardiogram and cardiac computed tomography (CT) or CT angiogram have limited roles in diagnosing LVAD infections due to their nonspecific findings, often affected by significant streaking and beam hardening artifacts from the metal device. In contrast, ¹⁸F-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET)/CT has repeatedly shown a high sensitivity and specificity for LVAD infection diagnosis, albeit in small number of subjects. Beyond its accuracy for detecting infection, FDG PET/CT can predict clinical outcome based on the location of LVAD infection. As a functional imaging tool, FDG PET/CT can demonstrate the extent and severity of LVAD infection, as well as infectious embolism and potential extra-cardiac source of infection, which are all critical for providing optimal patient care, justifying its judicious and precise use in the workup of LVAD infection.

Fluorodeoxyglucose Applications in Cardiac PET: Viability, Inflammation, Infection, and Beyond

With its high temporal and spatial resolution and relatively low radiation exposure, positron emission tomography (PET) is increasingly being used in the management of cardiac patients, particularly those with inflammatory cardiomyopathies such as sarcoidosis. This review discusses the role of PET imaging in assessing myocardial viability, inflammatory cardiomyopathies, and endocarditis; describes the different protocols needed to acquire images for specific imaging tests; and examines imaging interpretation for each image dataset-including identification of the mismatch defect in viability imaging, which is associated with significant improvement in LV function after revascularization. We also review the role of fluorodeoxyglucose PET in cardiac sarcoidosis diagnosis, the complementary role of magnetic resonance imaging in inflammatory cardiomyopathy, and the emerging use of cardiac PET in prosthetic valve endocarditis.

Positron emission tomography imaging in cardiovascular disease

Positron emission tomography (PET) imaging is useful in cardiovascular disease across several areas, from assessment of myocardial perfusion and viability, to highlighting atherosclerotic plaque activity and measuring the extent of cardiac innervation in heart failure. Other important roles of PET have emerged in prosthetic valve endocarditis, implanted device infection, infiltrative cardiomyopathies, aortic stenosis and cardio-oncology. Advances in scanner technology, including hybrid PET/MRI and total body PET imaging, as well as the development of novel PET tracers and cardiac-specific postprocessing techniques using artificial intelligence will undoubtedly continue to progress the field.

Diagnosis of Infective Endocarditis by Subtype Using 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: A Contemporary Meta-Analysis

Background Infective endocarditis (IE) remains a difficult to diagnose condition associated with high mortality. ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) has recently emerged as another IE imaging modality, although diagnostic accuracy varies across observational studies and types of IE. This meta-analysis assessed the diagnostic performance of ¹⁸F-FDG PET/CT for IE and its subtypes. Methods We searched Pubmed, Cochrane, and Embase from January 1980 to September 2019 for studies reporting both sensitivity and specificity of ¹⁸F-FDG PET/CT for IE. Meta-Disc 1.4 was used to pool data for all cases of IE and its subgroups of native valve IE, prosthetic valve IE, and cardiac implantable electronic devices IE. Results We screened 2566 records from the search, assessed 52 full-text articles, and included 26 studies totaling 1358 patients (509 IE cases). Pooled sensitivity and specificity (95% CI, inconsistency I-square statistic) were 0.74 (0.70-0.77, 71.5%) and 0.88 (0.86-0.91, 78.5%) for all cases of endocarditis. Corresponding parameters for native valve IE were sensitivity 0.31 (0.21-0.41, 29.4%) and specificity 0.98 (0.95-0.99, 34.4%); for prosthetic valve IE: sensitivity 0.86 (0.81-0.89, 60.0%) and specificity 0.84 (0.79-0.88, 75.2%); and for cardiac implantable electronic devices IE: sensitivity 0.72 (0.61-0.81, 76.2%) and specificity 0.83 (0.75-0.89, 83.6%). Pooled sensitivities and specificities were higher for the 17 studies since 2015 than the 9 studies published before 2015. Conclusions ¹⁸F-FDG PET/CT had high specificity for all IE subtypes; however, sensitivity was markedly lower for native valve IE than prosthetic valve IE and cardiac implantable electronic devices IE. It is, therefore, a useful adjunct modality for assessing endocarditis, especially in the challenging scenarios of prosthetic valve IE and cardiac implantable electronic devices IE, with improving performance over time, related to advances in ¹⁸F-FDG PET/CT techniques.

A tale of two technologies: Can nuclear cardiology survive the emergence of cardiac CT the seventeenth annual Mario S. Verani lectureship

The Mario S. Verani Lectureship has traditionally been an opportunity for presenters to reflect on the state of nuclear cardiology in clinical practice and expound on new innovations in the field. Mario Verani was a visionary who embraced change and, as a cardiologist, sought to define where other cardiac imaging techniques might complement nuclear cardiology for improving patient care. Over the last decade, nuclear cardiology and cardiac computed tomography (CT) have developed in parallel with both expanding beyond the evaluation of coronary artery disease. However, many consider cardiac CT a formidable threat to nuclear cardiology due to pivotal technical innovations and its subsequent exponential growth in recent years. It is only fitting that this year's lectureship explore the relative value of both techniques in evaluating and managing cardiac disease, their relative strengths and weaknesses, and the potential value of combining nuclear cardiology and cardiac CT imaging for enhancing patient management. To Mario, my mentor, colleague for over 20 years and friend, this lectureship is truly in honor and remembrance of you.