Role of 18F-FDG PET/CT in the diagnosis of infective endocarditis in patients with an implanted cardiac device: a prospective study

Risk of Cardiac Implantable Electronic Device Infection in Patients with Bloodstream Infection: Microbiologic Effect in the Era of Positron Emission Tomography-Computed Tomography

PURPOSE OF REVIEW

Bloodstream infection (BSI) in patients with cardiac implantable electronic devices (CIEDs) is common and can prompt challenges in defining optimal management. We provide a contemporary narrative review of this topic and propose a pathogen-dependent clinical approach to patient management.

RECENT FINDINGS

BSI due to staphylococci, viridans group streptococci, and enterococci is associated with an increased risk of underlying CIED infection, while the risk of CIED infection due to other organisms is poorly defined. There is growing evidence that positron emission tomography-computed tomography may be helpful in some patients with BSI and underlying CIED. Twenty studies were included to examine the impact of microbiologic findings on the risk of CIED infection among patients with BSI. Diagnosis of CIED infection in patients with BSI without pocket findings is often difficult, necessitating the use of novel diagnostic tools to help guide the clinician in subsequent patient management.

Is Imaging Bacteria with PET a Realistic Option or an Illusion?

The application of [¹⁸F]-fluorodeoxyglucose ([¹⁸F]FDG) as a radiotracer to detect sites of inflammation (either due to bacterial infection or primary inflammation) has led to exploring the role of PET in visualizing bacteria directly at sites of infection. However, the results from such efforts are controversial and inconclusive so far. We aimed to assess the limitations of PET as an effective modality in the diagnosis of bacterial infections. Inflammation due to bacterial infections can be visualized by using [¹⁸F]FDG-PET. However, the non-specificity of [¹⁸F]FDG makes it undesirable to visualize bacteria as the underlying cause of inflammation. Hence, more specific radiotracers that possibly bind to or accumulate in bacteria-specific receptors or enzymes are being explored. Several radiotracers, including 2-deoxy-2-[¹⁸F]fluorosorbitol ([¹⁸F]FDS), 6-[¹⁸F]-fluoromaltose, [¹¹C]para-aminobenzoic acid ([¹¹C]PABA), radiolabeled trimethoprim (¹¹C-TMP) and its analog fluoropropyl-trimethoprim (¹⁸F-FPTMP), other radiolabeled sugars, and antimicrobial drugs have been used to image microorganisms. Unfortunately, no progress has been made in translating the results to routine human use; feasibility and other factors have constrained their success in clinical settings. In the current article, we discuss the limitations of direct bacterial visualization with PET tracers, but emphasize the important role of [¹⁸F]FDG-PET as the only option for detecting evidence of infection.

Risk factors for Gram-negative bacterial infection of cardiovascular implantable electronic devices: multicentre observational study (CarDINe Study)

BACKGROUND

Infections of cardiovascular implantable electronic devices (CIED) are mainly due to Gram-positive bacteria (GPB). Data about Gram-negative bacteria CIED (GNB-CIED) infections are limited. This study aimed to investigate risk factors, clinical and diagnostic characteristics, and outcome of patients with GNB-CIED.

METHODS

A multicentre, international, retrospective, case-control-control study was performed on patients undergoing CIED implantation from 2015 to 2019 in 17 centres across Europe. For each patient diagnosed with GNB-CIED, one matching control with GPB-CIED infection and two matching controls without infection were selected.

RESULTS

A total of 236 patients were enrolled: 59 with GNB-CIED infection, 59 with GPB-CIED infection and 118 without infection. No between-group differences were found regarding clinical presentation, diagnostic and therapeutic management. A trend toward a higher rate of fluorodeoxyglucose positron emission computed tomography (FDG PET/CT) positivity was observed among patients with GNB than in those with GPB-CIED infection (85.7% vs. 66.7%; P = 0.208). Risk factors for GNB-CIED infection were Charlson Comorbidity Index Score (relative risk reduction, RRR = 1.211; P = 0.011), obesity (RRR = 5.122; P = 0.008), ventricular-pacing ventricular-sensing inhibited-response pacemaker implantation (RRR = 3.027; P = 0.006) and right subclavian vein site of implantation (RRR = 5.014; P = 0.004). At 180-day survival analysis, GNB-CIED infection was associated with increased mortality risk (HR = 1.842; P = 0.067).

CONCLUSIONS

Obesity, high number of comorbidities and right subclavian vein implantation site were associated with increased risk of GNB-CIED infection. A prompt therapeutic intervention that may be guided using FDG PET/CT is suggested in patients with GNB-CIED infection, considering the poorer outcome observed in this group.

Cardiovascular positron emission tomography: established and emerging role in cardiovascular diseases

Cardiac positron emission tomography (PET) imaging has established themselves firmly as excellent and reliable functional imaging modalities in assessment of the spectrum of coronary artery disease. With the explosion of technology advances and the dream of flow quantification now a reality, the value of PET is now well realized. Cardiac PET has proved itself as precise imaging modality that provides functional imaging of the heart in addition to anatomical imaging. It has established itself as one of the best available techniques for evaluation of myocardial viability. Hybrid PET/computed tomography provides simultaneous integration of coronary anatomy and function with myocardial perfusion and metabolism, thereby improving characterization of the dysfunctional area and chronic coronary artery disease. The availability of quantitative myocardial blood flow evaluation with PET provides additional prognostic information and increases diagnostic accuracy in the management of patients with coronary artery disease. Hybrid imaging seems to hold immense potential in optimizing management of cardiovascular diseases and furthering clinical research.

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.

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.

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.

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.

Cardiac Sarcoidosis Mimicking Anterior Myocardial Infarction

A 58-year-old asymptomatic man with electrocardiogram (ECG) abnormality was referred to our institution for cardiac exams. His ECG showed a bifascicular block, and the echocardiography demonstrated a wall motion abnormality in apex. Stress-rest myocardial perfusion imaging (MPI) showed a significant defect in anterior wall with partial redistribution at rest. He was suspected of having an anterior myocardial infarction (MI) and underwent cardiac catheterization. However, coronary angiography (CAG) revealed no significant coronary atherosclerosis. Cardiovascular magnetic resonance imaging (CMR) was performed to evaluate the extent of myocardial infarction. Late gadolinium enhancement (LGE) demonstrated a significant epicardial and midmyocardial LGE in the multiple site including anterior, anteroseptal, lateral, inferior wall, and basal right ventricle junction, which strongly indicated that the fibrosis was due to cardiac sarcoidosis (CS).A myocardial perfusion defect in anterior wall shown in the MPI revealed the fibrosis as an atypical finding mimicking anterior MI.

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.

Procedural recommendations of cardiac PET/CT imaging: standardization in inflammatory-, infective-, infiltrative-, and innervation- (4Is) related cardiovascular diseases: a joint collaboration of the EACVI and the EANM: summary

With this summarized document we share the standard for positron emission tomography (PET)/(diagnostic)computed tomography (CT) imaging procedures in cardiovascular diseases that are inflammatory, infective, infiltrative, or associated with dysfunctional innervation (4Is) as recently published in the European Journal of Nuclear Medicine and Molecular Imaging. This standard should be applied in clinical practice and integrated in clinical (multicentre) trials for optimal standardization of the procedurals and interpretations. A major focus is put on procedures using [¹⁸F]-2-fluoro-2-deoxyglucose ([¹⁸F]FDG), but 4Is PET radiopharmaceuticals beyond [¹⁸F]FDG are also described in this summarized document. Whilst these novel tracers are currently mainly applied in early clinical trials, some multicentre trials are underway and we foresee in the near future their use in clinical care and inclusion in the clinical guidelines. Diagnosis and management of 4Is related cardiovascular diseases are generally complex and often require a multidisciplinary approach by a team of experts. The new standards described herein should be applied when using PET/CT and PET/magnetic resonance, within a multimodality imaging framework both in clinical practice and in clinical trials for 4Is cardiovascular indications.

ACR Appropriateness Criteria® Infective Endocarditis

Infective endocarditis can involve a normal, abnormal, or prosthetic cardiac valve. The diagnosis is typically made clinically with persistently positive blood cultures, characteristic signs and symptoms, and echocardiographic evidence of valvular vegetations or valvular complications such as abscess, dehiscence, or new regurgitation. Imaging plays an important role in the initial diagnosis of infective endocarditis, identifying complications, prognostication, and informing the next steps in therapy. This document outlines the initial imaging appropriateness of a patient with suspected infective endocarditis and for additional imaging in a patient with known or suspected infective endocarditis. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

A Historical Perspective of Cardiac Implantable Electronic Device Infection: How a Menace Can Drive Technological and Clinical Improvement

In recent decades there has been a relevant increase in the implantation rate of cardiac implantable electronic devices (CIEDs), albeit with relevant geographical inhomogeneities. Despite the positive impact on clinical outcomes, the possibility of major complications is not negligible, particularly with respect to CIED infections. CIED infections significantly affect morbidity and mortality, especially in instances of delayed diagnosis and appropriate treatment. In the present review, we will start to depict the factors underlying the development of CIED infection as well as the difficulties related to its diagnosis and treatment. We will explain the reasons underlying the need to focus on prophylaxis rather than treatment, in view of the poor outcomes despite improvements in lead extraction procedures. This will lead to the consideration of management of this complication in a hub-spoke manner, and to our analysis of the several technological and procedural improvements developed to minimize this complication. These include prolongation of CIED longevity, the development of leadless devices, and integrated prophylactic approaches. We will conclude with a discussion regarding new devices and strategies under development. This complete excursus will provide the reader with a new perspective on how a major complication can drive technological improvements.

PET/CT with 18F-FDG in suspected intracardiac device-related infections: analysis of performance and diagnostic usefulness

INTRODUCTION AND OBJECTIVES

Cardiac device-related infections (CDRI) may be life-threatening and require early and accurate diagnosis. The aims of this study were to analyze the performance of positron emission tomography-computed tomography (PET/CT) in suspected CDRI, to assess changes to the initial diagnosis, and to identify a clinical subgroup deriving the greatest benefit from this imaging modality.

METHODS

Retrospective study including patients evaluated by PET/CT for suspected CDRI from 2011 to 2018. We assessed PET/CT performance and the agreement between the initial, post-PET and definitive diagnoses. We also assessed changes in the diagnosis, depending on initial clinical suspicion, to identify patients deriving the greatest benefit from PET/CT.

RESULTS

We included 44 patients. The prevalence of endocarditis was 57%. The sensitivity and specificity of PET/CT for the diagnosis of infective endocarditis were 0.84 and 0.95, respectively. Post-PET diagnosis improved the initial diagnosis by 45%. PET/CT correctly reclassified 57% of patients with initial suspicion of generator pocket infection by detecting lead infection.

CONCLUSIONS

PET/CT showed high diagnostic performance in suspected of CDRI and significantly improved the conventional diagnostic approach, especially in patients with initial suspicion of focal infection.

18F-fluorodeoxyglucose positron emission tomography/computed tomography for the diagnosis of native valve infective endocarditis: A prospective study

BACKGROUND

¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) has recently been added as a major criterion in the European Society of Cardiology (ESC) 2015 infective endocarditis guidelines. PET/CT is currently used in patients with suspected prosthetic valve and cardiac device-related endocarditis. However, the value of the ESC classification and the clinical impact of PET findings are unknown in patients with native valve endocarditis (NVE).

AIMS

Our aims were: to assess the value of the ESC criteria (including PET/CT) in NVE; to determine the usefulness of PET/CT concerning embolic detection; and to describe a new PET/CT feature (diffuse splenic uptake).

METHODS

Between 2012 and 2017, 75 patients with suspected NVE were included prospectively, after exclusion of patients with uninterpretable or unfeasible PET/CT. Using gold standard expert consensus, 63 cases of infective endocarditis were confirmed and 12 were rejected.

RESULTS

Significant valvular uptake was observed in 11 of 63 patients with definite NVE and in no patients who had the diagnosis of infective endocarditis rejected (sensitivity 17.5%, specificity 100%). Among the 63 patients with NVE, a peripheral embolism or mycotic aneurysm was observed in 20 (31.7%) cases. Application of the ESC criteria increased Duke criteria sensitivity from 63.5% to 69.8% (P<0.001), without a change in specificity. Diffuse splenic uptake was observed in 39 (52.0%) patients, including 37 (58.7%) with a final diagnosis of NVE (specificity 83.3%).

CONCLUSIONS

¹⁸F-FDG PET/CT has poor sensitivity but high specificity in the diagnosis of NVE. The usefulness of ¹⁸F-FDG PET/CT is high for embolic detection. Diffuse splenic uptake represents a possible new diagnostic criterion for NVE.

Intraoperative transesophageal echocardiography: A complement to 18F-fluorodeoxyglucose positron emission tomography-computed tomography in localizing pacemaker lead endocarditis

Lead endocarditis (LE) is a serious complication of permanent trans-venous pacing. Localizing LE may be challenging with conventional imaging modalities. 2-deoxy-2-[fluorine-18] fluoro-D-glucose positron emission tomography–computed tomography (FDG PET/CT) has recently emerged as a promising tool in the diagnosis of LE particularly in cases with normal echocardiographic imaging findings and/or negative blood culture. However, this technique is associated with some drawbacks. Knowledge of these drawbacks and correlating its limitations with other imaging modality is essential for the echocardiographer while evaluating such patient. We report a case where transesophageal echocardiography was complementary to FDG PET/CT in the diagnosis and localization of vegetation over pacemaker leads during intraoperative period.

Procedural recommendations of cardiac PET/CT imaging: standardization in inflammatory-, infective-, infiltrative-, and innervation (4Is)-related cardiovascular diseases: a joint collaboration of the EACVI and the EANM

With this document, we provide a standard for PET/(diagnostic) CT imaging procedures in cardiovascular diseases that are inflammatory, infective, infiltrative, or associated with dysfunctional innervation (4Is). This standard should be applied in clinical practice and integrated in clinical (multicenter) trials for optimal procedural standardization. A major focus is put on procedures using [¹⁸F]FDG, but 4Is PET radiopharmaceuticals beyond [¹⁸F]FDG are also described in this document. Whilst these novel tracers are currently mainly applied in early clinical trials, some multicenter trials are underway and we foresee in the near future their use in clinical care and inclusion in the clinical guidelines. Finally, PET/MR applications in 4Is cardiovascular diseases are also briefly described. Diagnosis and management of 4Is-related cardiovascular diseases are generally complex and often require a multidisciplinary approach by a team of experts. The new standards described herein should be applied when using PET/CT and PET/MR, within a multimodality imaging framework both in clinical practice and in clinical trials for 4Is cardiovascular indications.

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

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

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

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

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.

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

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

The never-ending story of CIED infection prevention: Shall we WRAP-IT and go?

CIED infection is perceived as substantial, ranging from 1% to 4% in literature depending on different studies and on the population profile, and can appear either as surgical site or endovascular infection or both. Several factors have been found to be associated to CIED infection, that can be summarized as patient-related (clinical profile, associated comorbidities, ongoing treatment as anticoagulants and immunosuppressants), Procedure-related (complexity of CIED surgery, type of surgery, previous pocket exploration), and center-/operator-related (center/operator volume). Thus, it is difficult to disentangle the extent of benefit that any intervention may offer to decrease this threatened complication, owing to its multifaceted complexity. The recently completed PADIT and WRAP-IT trials have significantly improved our knowledge in this field (nearly 20 000 patients enrolled), reporting an infection rate of 1% to 1.2% in control-arm patients and a 20% to 67% infection decrease when incremental antibiotic prophylaxis is added on top of optimized preventative strategies. Observational registries highlighted that participation in a prospective survey of CIED infection dramatically decrease infection rate by optimization of antisepsis protocols and operator awareness, that explains the low event rate observed in PADIT and WRAP-IT. While this consideration prompts each center to engage into a proactive infection prevention program, it makes a point in favor of antibiotic prophylaxis delivered locally in 7 days or more, as enabled by TYRX in the WRAP-IT trial. However, care sustainability (the number needed to treat in the most favorable WRAP-IT scenario is 100) suggests further analysis to understand the settings (patient- or procedure-related) most likely to benefit by such an enhanced prevention strategy.

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

OBJECTIVE

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Meta-analysis of 18F-FDG PET/CT in the diagnosis of infective endocarditis

BACKGROUND

The current diagnosis of infective endocarditis (IE) is based on the modified Duke criteria, which has approximately 80% sensitivity for the diagnosis of native valve endocarditis (NVE), with lower sensitivity for the diagnosis of prosthetic valve endocarditis (PVE) and culture-negative endocarditis. There is preliminary evidence that 18F-FDG PET/CT is an adjunctive diagnostic test with high accuracy reported in small studies to date. We therefore performed a meta-analysis of studies evaluating the use of PET/CT in the diagnosis of IE to establish a more precise estimate of accuracy.

METHODS

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

RESULTS

We identified 13 studies involving 537 patients that were included in the meta-analysis. The pooled sensitivity of PET/CT for diagnosis of IE was 76.8% (95% CI 71.8-81.4%; Q = 39.9, P < 0.01; I2 = 69.9%) and the pooled specificity was 77.9% (95% CI 71.9-83.2%; Q = 44.42, P < 0.01; I2 = 73.0%). Diagnostic accuracy was improved for PVE with sensitivity of 80.5% (95% CI 74.1-86.0%; Q = 25.5, P < 0.01; I2 = 72.5%) and specificity of 73.1% (95% CI 63.8-81.2%; Q = 32.1, P < 0.01; I2 = 78.2%). Additional extracardiac foci of infection were found on 17% of patients on whole body PET/CT.

CONCLUSION

PET/CT is a useful adjunctive diagnostic tool in the evaluation of diagnostically challenging cases of IE, particularly in prosthetic valve endocarditis. It also has the potential to detect clinically relevant extracardiac foci of infection, malignancy, and other sources of inflammation leading to more appropriate treatment regimens and surgical intervention.

Cardiovascular Implantable Electronic Device Infections

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Recommendations on nuclear and multimodality imaging in IE and CIED infections

In the latest update of the European Society of Cardiology (ESC) guidelines for the management of infective endocarditis (IE), imaging is positioned at the centre of the diagnostic work-up so that an early and accurate diagnosis can be reached. Besides echocardiography, contrast-enhanced CT (ce-CT), radiolabelled leucocyte (white blood cell, WBC) SPECT/CT and [¹⁸F]FDG PET/CT are included as diagnostic tools in the diagnostic flow chart for IE. Following the clinical guidelines that provided a straightforward message on the role of multimodality imaging, we believe that it is highly relevant to produce specific recommendations on nuclear multimodality imaging in IE and cardiac implantable electronic device infections. In these procedural recommendations we therefore describe in detail the technical and practical aspects of WBC SPECT/CT and [¹⁸F]FDG PET/CT, including ce-CT acquisition protocols. We also discuss the advantages and limitations of each procedure, specific pitfalls when interpreting images, and the most important results from the literature, and also provide recommendations on the appropriate use of multimodality imaging.

18F-FDG-PET/CT Imaging to Diagnose Septic Emboli and Mycotic Aneurysms in Patients with Endocarditis and Cardiac Device Infections

PURPOSE OF REVIEW

This review analyzes recent studies evaluating the diagnostic value of ¹⁸F-FDG-PET/CT for the detection of peripheral emboli and secondary infectious foci in patients with infective endocarditis and cardiac device infections.

RECENT FINDINGS

Detection of extracardiac septic localizations in patients with infective endocarditis and cardiac device infections is crucial, as it may impact the diagnosis, prognosis, and therapeutic management. Recent literature substantiated the clinical usefulness of ¹⁸F-FDG-PET/CT in this setting. ¹⁸F-FDG-PET/CT has proven its high diagnostic value for the detection of peripheral emboli in patients with infective endocarditis and cardiac device infections, substantially affecting patients' outcome and treatment. A multimodal approach, combining the high sensitivity of ¹⁸F-FDG-PET/CT with morphological imaging seems promising.

Molecular Imaging for the diagnosis of infective endocarditis: A systematic literature review and meta-analysis

BACKGROUND

Infective endocarditis (IE) is a serious, potentially life-threatening condition. Currently, the modified Duke criteria is used to assist with the diagnosis of IE, but it can still remain difficult. Growing data supports the potential use of molecular imaging to assist in the diagnosis of IE. Our objective was to understand the potential utility of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography-computed tomography (PET-CT), ⁶⁷Ga citrate and radiolabeled white blood cell (WBC) scintigraphy in the diagnosis of IE.

METHODS AND RESULTS

A systematic review of the literature and meta-analysis on the use of all 3 modalities in IE was conducted. The literature search identified 2753 articles. A total of 14 studies met the inclusion criteria (10 for ¹⁸F-FDG, 3 for WBC and 1 for both modalities). No ⁶⁷Ga citrate study met the inclusion criteria. Pooled sensitivity of ¹⁸F-FDG studies with adequate cardiac preparation for the diagnosis of IE was 81% (95% CI, 73%-86%) and pooled specificity was 85% (95% CI, 78%-91%). There was good overall accuracy with an area under the curve (AUC) of 0.897. Pooled sensitivity of WBC for the diagnosis of IE was 86% (95% CI, 77%-92%) and pooled specificity was 97% (95% CI, 92%-99%). The overall accuracy of WBC was excellent with an AUC of 0.957.

CONCLUSIONS

Both ¹⁸F-FDG and WBC have good sensitivity, specificity and accuracy for the diagnosis of IE. Both modalities are useful in the investigation of IE, and should be considered in cases where the diagnosis is uncertain.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

18F-FDG-PET/CT angiography in the diagnosis of infective endocarditis and cardiac device infection in adult patients with congenital heart disease and prosthetic material

OBJECTIVES

Infective endocarditis (IE) and cardiac device infection (CDI) are a major complication in the growing number of patients with congenital heart disease (CHD) reaching adulthood. We aimed to evaluate the added value of ¹⁸F-FDG-PET/CT angiography (PET/CTA) in the diagnosis of IE-CDI in adults with CHD and intravascular or intracardiac prosthetic material, in whom echocardiography (ECHO) and modified Duke Criteria (DC) have limitations because of the patients' complex anatomy.

METHODS

A prospective study was conducted in a referral center with multidisciplinary IE and CHD Units. PET/CTA and ECHO findings were compared in consecutive adult (≥18years) patients with CHD who have prosthetic material and suspected IE-CDI. The initial diagnosis using the DC and the diagnosis with the additional PET/CTA data (DC+PET/CTA) were compared with the final diagnostic consensus established by an expert team at three months.

RESULTS

Between November-2012 and April-2017, 25 patients (15 men; median age 40years) were included. Cases were initially classified as definite in 8 (32%), possible in 14 (56%) and rejected in 3 (12%). DC+PET/CTA allowed reclassification of 12/14 (86%) cases initially identified as possible IE. The sensitivity, specificity, PPV, NPV, and accuracy of DC at IE suspicion were 39.1%/83.3%/90.4%/25.5%/61.2%, respectively. The diagnostic performance increased significantly with addition of PET/CTA data: 87%/83.3%/95.4%/61.5%/85.1%, respectively. PET/CTA also provided an alternative diagnosis in 3 patients with rejected IE, and detected pulmonary embolisms in 3 patients.

CONCLUSIONS

PET/CTA was a useful diagnostic tool in the complex group of adult patients with CHD who have cardiac or intravascular prosthetic material and suspected IE or CDI, providing added diagnostic value to the modified DC (increased sensitivity) and improving case classification.

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

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSIONS

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

Graft infection after a Bentall procedure: A case series and systematic review of the literature

INTRODUCTION

The Bentall procedure is a cardiac surgery involving graft replacement of the aortic valve, aortic root and ascending aorta. Graft infection after Bentall's procedure (BGI) is infrequent but severe, and often difficult to diagnose and treat.

PATIENTS AND METHODS

A retrospective cohort study was performed using the Bordeaux endocarditis database of adult patients admitted to the Bordeaux University Medical Hospital for BGI between 2008 and 2014. Published case reports were identified in the literature.

RESULTS

We identified 10 BGI patients in the database and 13 in the literature. The majority of infections were late-onset (20/23) and occurred as a result of gram positive cocci bacterial infection (16/22). Detailed diagnoses of the described BGI were determined using echocardiography, computed tomography (CT) and positron emission tomography/CT (PET/CT). Labeled-leukocyte scintigraphy was not reported in any case. Prolonged antibiotic therapy and surgery were found to be the treatment of choice for BGI; however it was not always possible to perform a surgical intervention. Clinical relapses occurred even with a negative PET/CT, while PET/CT consistently positive for BGI occurred in the absence of clinical relapse. This suggests that the use of PET/CT for follow-up is questionable.

CONCLUSION

Diagnosis of BGI is difficult, due to the combination of clinical, biological, and radiological observations obtained through transesophageal echocardiography and CT. PET/CT is an alternative method to diagnosis BGI, but its impact on clinical management remains unclear. Current data suggests that if surgical replacement of the prosthesis is not possible, patients should be treated with prolonged antibiotic therapy.

Alternative Cardiac Imaging Modalities to Echocardiography for the Diagnosis of Infective Endocarditis

Infective endocarditis (IE) is a life-threatening disease. Considered the gold standard for the diagnosis of IE, the modified Duke criteria rely on echocardiographic findings to satisfy its major criterion. Echocardiography is an invaluable tool in the evaluation of patients with suspected IE but suffers from certain limitations. For example, it cannot differentiate vegetation from clot, or between infected and noninfected vegetation, and may miss vegetation and periannular extensions in the presence of prosthetic material. Therefore, alternative cardiac imaging modalities are needed. Nuclear imaging, particularly ¹⁸F-fluorodesoxyglucose positron emission tomography-computed tomography (CT), is becoming increasingly popular in the evaluation of patients for IE and has shown promise in diagnosing valvular and device-related IE when echocardiography results were inconclusive. Other techniques such as radiolabeled leukocyte scintigraphy and single-photon emission computed tomography with or without CT are less well studied, however. Cardiac CT angiography is also evolving as a powerful supplementary tool to echocardiography for the detection of perivalvular complications of IE and for preoperative evaluation of coronary anatomy. The combination of cardiac CT angiography and echocardiography is superior to either test alone in the diagnosis of IE and its complications. Although brain magnetic resonance imaging may impact prognosis and clinical management by identifying cerebral emboli in patients with IE, the role of cardiac and abdominal magnetic resonance imaging is less clear. In conclusion, with these additional diagnostic tools at our disposal, the diagnosis of IE may be achieved in a more timely and accurate manner to secure better clinical outcomes.

Diagnostic value of imaging in infective endocarditis: a systematic review

Sensitivity and specificity of the modified Duke criteria for native valve endocarditis are both suboptimal, at approximately 80%. Diagnostic accuracy for intracardiac prosthetic material-related infection is even lower. Non-invasive imaging modalities could potentially improve diagnosis of infective endocarditis; however, their diagnostic value is unclear. We did a systematic literature review to critically appraise the evidence for the diagnostic performance of these imaging modalities, according to PRISMA and GRADE criteria. We searched PubMed, Embase, and Cochrane databases. 31 studies were included that presented original data on the performance of electrocardiogram (ECG)-gated multidetector CT angiography (MDCTA), ECG-gated MRI, ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET/CT, and leucocyte scintigraphy in diagnosis of native valve endocarditis, intracardiac prosthetic material-related infection, and extracardiac foci in adults. We consistently found positive albeit weak evidence for the diagnostic benefit of ¹⁸F-FDG PET/CT and MDCTA. We conclude that additional imaging techniques should be considered if infective endocarditis is suspected. We propose an evidence-based diagnostic work-up for infective endocarditis including these non-invasive techniques.

Clinical Utility and Future Applications of PET/CT and PET/CMR in Cardiology

Over the past several years, there have been major advances in cardiovascular positron emission tomography (PET) in combination with either computed tomography (CT) or, more recently, cardiovascular magnetic resonance (CMR). These multi-modality approaches have significant potential to leverage the strengths of each modality to improve the characterization of a variety of cardiovascular diseases and to predict clinical outcomes. This review will discuss current developments and potential future uses of PET/CT and PET/CMR for cardiovascular applications, which promise to add significant incremental benefits to the data provided by each modality alone.