Cost-effectiveness of routine (18)F-FDG PET/CT in high-risk patients with gram-positive bacteremia

EANM consensus document on the use of [18F]FDG PET/CT in fever and inflammation of unknown origin

PURPOSE

Patients with fever and inflammation of unknown origin (FUO/IUO) are clinically challenging due to variable clinical presentations with nonspecific symptoms and many differential diagnoses. Positron emission tomography/computed tomography (PET/CT) with 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) is increasingly used in FUO and IUO, but the optimal diagnostic strategy remains controversial. This consensus document aims to assist clinicians and nuclear medicine specialists in the appropriate use of [18F]FDG-PET/CT in FUO and IUO based on current evidence.

METHODS

A working group created by the EANM infection and inflammation committee performed a systematic literature search based on PICOs with "patients with FUO/IUO" as population, "[18F]FDG-PET/CT" as intervention, and several outcomes including pre-scan characteristics, scan protocol, diagnostic yield, impact on management, prognosis, and cost-effectiveness.

RESULTS

We included 68 articles published from 2001 to 2023: 9 systematic reviews, 49 original papers on general adult populations, and 10 original papers on specific populations. All papers were analysed and included in the evidence-based recommendations.

CONCLUSION

FUO and IUO remains a clinical challenge and [18F]FDG PET/CT has a definite role in the diagnostic pathway with an overall diagnostic yield or helpfulness in 50-60% of patients. A positive scan is often contributory by directly guiding treatment or subsequent diagnostic procedure. However, a negative scan may be equally important by excluding focal disease and predicting a favorable prognosis. Similar results are obtained in specific populations such as ICU-patients, children and HIV-patients.

Evaluating the use of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in the workup of Staphylococcus aureus bacteraemia: a cost-utility analysis

OBJECTIVES

The use of positron emission tomography/computed tomography (PET/CT) in the evaluation of patients with Staphylococcus aureus bacteraemia can improve the diagnosis of infectious foci and guide clinical management. We aimed to evaluate the cost-utility of PET/CT among adults hospitalized with Staphylococcus aureus bacteraemia.

METHODS

A cost-utility analysis was conducted from the healthcare payer perspective using a probabilistic Markov cohort model assessing three diagnostic strategies: (a) PET/CT in all patients, (b) PET/CT in high-risk patients only, and (c) routine diagnostic workup. Primary outcomes were quality-adjusted life years (QALYs), costs in Canadian dollars, and an incremental cost-effectiveness ratio. Deterministic and probabilistic sensitivity analyses were conducted to evaluate parameter uncertainty.

RESULTS

Routine workup resulted in an average of 16.64 QALYs from the time of diagnosis at a lifetime cost of $209 060/patient. This was dominated by PET/CT in high-risk patients (i.e. greater effectiveness at lower costs) with average 16.88 QALYs at a cost of $199 552. Compared with PET/CT in high-risk patients only, PET/CT for all patients cost on average $11 960 more but resulted in 0.14 more QALYs, giving an incremental cost-effectiveness ratio of $83 500 (cost per additional QALY gained); however, there was a high degree of uncertainty comparing these two strategies. At a willingness-to-pay threshold of $50 000/QALY, PET/CT in high-risk patients was the most cost-effective strategy in 58.6% of simulations vs. 37.9% for PET/CT in all patients.

DISCUSSION

Our findings suggest that a strategy of using PET/CT in high-risk patients is more cost-effective than no PET/CT. Randomized controlled trials should be conducted to evaluate the use of PET/CT in different patient groups.

Randomized clinical trial: Long-term Staphylococcus aureus decolonization in patients on home parenteral nutrition

BACKGROUND & AIMS

Staphylococcus aureus decolonization has proven successful in prevention of S. aureus infections and is a key strategy to maintain venous access and avoid hospitalization in patients receiving home parenteral nutrition (HPN). We aimed to determine the most effective and safe long-term S. aureus decolonization regimen.

METHODS

A randomized, open-label, multicenter clinical trial was conducted. Adult intestinal failure patients with HPN support and carrying S. aureus were randomly assigned to a 'continuous suppression' (CS) strategy, a repeated chronic topical antibiotic treatment or a 'search and destroy' (SD) strategy, a short and systemic antibiotic treatment. Primary outcome was the proportion of patients in whom S. aureus was totally eradicated during a 1-year period. Secondary outcomes included risk factors for decolonization failure and S. aureus infections, antimicrobial resistance, adverse events, patient compliance and cost-effectivity.

RESULTS

63 participants were included (CS 31; SD 32). The mean 1-year S. aureus decolonization rate was 61% (95% CI 44, 75) for the CS group and 39% (95% CI 25, 56) for the SD group with an OR of 2.38 (95% CI 0.92, 6.11, P = 0.07). More adverse effects occurred in the SD group (P = 0.01). Predictors for eradication failure were a S. aureus positive caregiver and presence of a (gastro)enterostomy.

CONCLUSION

We did not demonstrate an increased efficacy of a short and systemic S. aureus decolonization strategy over a continuous topical suppression treatment. The latter may be the best option for HPN patients as it achieved a higher long-term decolonization rate and was well-tolerated (NCT03173053).

Impact of 18F-FDG-PET/CT on the management of Staphylococcus aureus bacteraemia: a retrospective observational study

OBJECTIVES

To assess the impact of ¹⁸F-FDG-PET/CT on the diagnosis and management of patients with Staphylococcus aureus bacteraemia (SAB).

METHODS

Post hoc analysis of a prospective cohort of consecutive adult patients diagnosed with SAB (January 2013-December 2017). Patients who underwent ¹⁸F-FDG-PET/CT at the discretion of the attending physician were included. Endpoints were the identification of previously unknown infectious foci and changes in clinical management, defined as changes in the duration or class of antibiotic therapy, a surgical procedure on the source of infection or a change in the decision to remove or retain an implantable device.

RESULTS

We included 39 patients (median age: 69 years, IQR:60-79). Fifteen (39%) patients did not have an infectious focus identified before ¹⁸F-FDG-PET/CT). Thirty new infectious foci were detected in 22/39 (56%) patients. In 11/15 (73%) patients without an identified focus at least one infectious focus was detected by ¹⁸F-FDG-PET/CT. In 22/26 (85%) patients with implantable devices, ¹⁸F-FDG-PET/CT confirmed or ruled out infection or detected local complications. Out of 13 device infections, 10 were detected by ¹⁸F-FDG-PET/CT (7/10 for the first time). In 19/39 (49%) patients ¹⁸F-FDG-PET/CT results led to changes in clinical management (15 changes in antibiotic therapy, 2 device removals, 2 surgical procedures, 1 avoidance of a surgical procedure).

CONCLUSIONS

¹⁸F-FDG-PET/CT may be a useful asset in the management of selected SAB cases, allowing the identification of previously undetected infectious foci and optimization of therapy, particularly in patients with endovascular devices. Indication should be made on a case-by-case basis.

Leclercia adecarboxylata infective endocarditis in a man with mitral stenosis: A case report and review of the literature

BACKGROUND

Infective endocarditis (IE) is a rare disease with a high mortality rate. Leclercia adecarboxylata (L. adecarboxylata) is a movable Gram-negative bacillus of enterobacteriaceae, and it can rarely be a pathogen which often affects immunodeficient patients. There are about three cases of immunocompetent patients with monomicrobial L. adecarboxylata infection. There are only three reported cases of IE caused by L. adecarboxylata in the world. The mitral valve is often affected in IE, and the prognosis for IE with mitral valve lesions is often poor.

CASE SUMMARY

A 51-year-old man was found to have moderate to severe mitral stenosis on echocardiography. He came to our Cardiothoracic Surgery Department for surgical management. A diastolic murmur was heard on auscultation of the heart in the mitral region. On the second day of hospitalisation, he presented with slurred speech, reduced muscle strength in the left limb, and acute cerebral infarction on cranial computed tomography. Surgical treatment was decided to postpone. On the ninth day of admission, the patient developed a sudden high fever and shock and was transferred to the Cardiac Intensive Care Unit, where echocardiogram revealed an anterior mitral valve leaflet vegetation. After empirical anti-infective treatment with vancomycin (1g q12h), an emergency valve replacement was performed. Bacterial culture identified L. adecarboxylata. Anti-infective treatment with piperacillin-tazobactam (4.5g q8h) was added for 4 wk. Follow-up echocardiography showed normal bioprosthetic valve function after mitral valve replacement.

CONCLUSION

We report the first case of L. adecarboxylata IE in China, and clinicians should pay attention to this pathogen.

Optimal use of the FDG-PET/CT in the diagnostic process of fever of unknown origin (FUO): a comprehensive review

Numerous studies have clarified the usefulness of ¹⁸F-fluorodeoxyglucose (FDG)-PET/CT (positron emission tomography) for diagnosing the cause of fever of unknown origin (FUO). Various types of disease can cause FUO, but the cause remains unknown in a certain proportion of FUO, even when the advanced diagnostic methodologies are used. FDG-PET/CT is regarded as a second-line modality in the diagnostic process of FUO, and its potential to identify the cause of FUO will be maximized when the appropriate clinical considerations are understood. Accordingly, this review presents basic knowledge regarding FUO, and reports the current status of FDG-PET/CT applied to diagnosing the cause of FUO, including diagnostic performance, test protocols, possible factors influencing the diagnostic result, outcomes, and cost-effectiveness. This knowledge will enable effective future use of FDG-PET/CT to improve outcomes in patients with FUO.

Multimodality Imaging in the Diagnosis of Prosthetic Valve Endocarditis: A Brief Review

Infective endocarditis is a common and treatable condition that carries a high mortality rate. Currently the workup of infective endocarditis relies on the integration of clinical, microbiological and echocardiographic data through the use of the modified Duke criteria (MDC). However, in cases of prosthetic valve endocarditis (PVE) echocardiography can be normal or non-diagnostic in a high proportion of cases leading to decreased sensitivity for the MDC. Evolving multimodality imaging techniques including leukocyte scintigraphy (white blood cell imaging), 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), multidetector computed tomographic angiography (MDCTA), and cardiac magnetic resonance imaging (CMRI) may each augment the standard workup of PVE and increase diagnostic accuracy. While further studies are necessary to clarify the ideal role for each of these imaging techniques, nevertheless, these modalities hold promise in determining the diagnosis, prognosis, and care of PVE. We start by presenting a clinical vignette, then evidence supporting various modality strategies, balanced by limitations, and review of formal guidelines, when available. The article ends with the authors' summary of future directions and case conclusion.

PET/computed tomography in inpatients: part 1, international survey

PURPOSE

The purposes of this study are to (1) identify patterns of inpatient PET/computed tomography (CT) use in and outside of the USA and (2) characterize inpatient PET/CT use by location and indication.

MATERIALS AND METHODS

The study was deemed exempt by the Institutional Review Board. A survey link through REDCap was emailed to the Society of Nuclear Medicine and Molecular Imaging (SNMMI) members and PET Centers of Excellence members and posted on the SNMMI website. Data were collected from May 2018 to August 2018. Analyses were conducted using SAS Software 9.4 with the NPAR1WAY procedure. Differences were evaluated using the Kruskal-Wallis test with statistical significance defined as P ≤ 0.05.

RESULTS

A total of 124 people responded to the survey, 71.8% (89/124) in the USA, and 26.6% (33/124) outside the USA [1.6% (2/124) no response]. 81.5% (101/124) read inpatient PET/CTs. Median percent of inpatient PET/CTs was 8.0% (range 0-100). Use of inpatient PET/CT was different (P < 0.0001) in the USA (5%, range 0-80%) versus outside USA (17.7%, range 0-100%). Use of inpatient PET/CT was different by institution type: median percent of inpatient PET/CTs in community teaching hospitals was 4.5% (range 0-50) versus 1.1% (range 0-20) in community nonteaching, 10% (range 0-80) in academic medical centers, and 20.0% (range 6.3-40) in government-affiliated institutions (P = 0.0001).

CONCLUSIONS

Most US and non-US respondents read inpatients PET/CTs. Non-US respondents read a higher percentage of inpatient PET/CTs than US respondents. Respondents in government-affiliated institutions read the highest percent of inpatient PET/CTs and community nonteaching institutions the least. Results of this survey may help physicians evaluate whether their practice of providing inpatient PET/CT fits with current practice patterns.

European Heart Rhythm Association (EHRA) international consensus document on how to prevent, diagnose, and treat cardiac implantable electronic device infections-endorsed by the Heart Rhythm Society (HRS), the Asia Pacific Heart Rhythm Society (APHRS), the Latin American Heart Rhythm Society (LAHRS), International Society for Cardiovascular Infectious Diseases (ISCVID) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS)

Pacemakers, implantable cardiac defibrillators, and cardiac resynchronization therapy devices are potentially life-saving treatments for a number of cardiac conditions, but are not without risk. Most concerning is the risk of a cardiac implantable electronic device (CIED) infection, which is associated with significant morbidity, increased hospitalizations, reduced survival, and increased healthcare costs. Recommended preventive strategies such as administration of intravenous antibiotics before implantation are well recognized. Uncertainties have remained about the role of various preventive, diagnostic, and treatment measures such as skin antiseptics, pocket antibiotic solutions, anti-bacterial envelopes, prolonged antibiotics post-implantation, and others. Guidance on whether to use novel device alternatives expected to be less prone to infections and novel oral anticoagulants is also limited, as are definitions on minimum quality requirements for centres and operators and volumes. Moreover, an international consensus document on management of CIED infections is lacking. The recognition of these issues, the dissemination of results from important randomized trials focusing on prevention of CIED infections, and observed divergences in managing device-related infections as found in an European Heart Rhythm Association worldwide survey, provided a strong incentive for a 2019 International State-of-the-art Consensus document on risk assessment, prevention, diagnosis, and treatment of CIED infections.

European Heart Rhythm Association (EHRA) international consensus document on how to prevent, diagnose, and treat cardiac implantable electronic device infections-endorsed by the Heart Rhythm Society (HRS), the Asia Pacific Heart Rhythm Society (APHRS), the Latin American Heart Rhythm Society (LAHRS), International Society for Cardiovascular Infectious Diseases (ISCVID) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS)

Pacemakers, implantable cardiac defibrillators, and cardiac resynchronization therapy devices are potentially life-saving treatments for a number of cardiac conditions, but are not without risk. Most concerning is the risk of a cardiac implantable electronic device (CIED) infection, which is associated with significant morbidity, increased hospitalizations, reduced survival, and increased healthcare costs. Recommended preventive strategies such as administration of intravenous antibiotics before implantation are well recognized. Uncertainties have remained about the role of various preventive, diagnostic, and treatment measures such as skin antiseptics, pocket antibiotic solutions, anti-bacterial envelopes, prolonged antibiotics post-implantation, and others. Guidance on whether to use novel device alternatives expected to be less prone to infections and novel oral anticoagulants is also limited, as are definitions on minimum quality requirements for centres and operators and volumes. Moreover, an international consensus document on management of CIED infections is lacking. The recognition of these issues, the dissemination of results from important randomized trials focusing on prevention of CIED infections, and observed divergences in managing device-related infections as found in an European Heart Rhythm Association worldwide survey, provided a strong incentive for a 2019 International State-of-the-art Consensus document on risk assessment, prevention, diagnosis, and treatment of CIED infections.

European Heart Rhythm Association (EHRA) international consensus document on how to prevent, diagnose, and treat cardiac implantable electronic device infections-endorsed by the Heart Rhythm Society (HRS), the Asia Pacific Heart Rhythm Society (APHRS), the Latin American Heart Rhythm Society (LAHRS), International Society for Cardiovascular Infectious Diseases (ISCVID), and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS)

Pacemakers, implantable cardiac defibrillators, and cardiac resynchronization therapy devices are potentially lifesaving treatments for a number of cardiac conditions but are not without risk. Most concerning is the risk of a cardiac implantable electronic device (CIED) infection, which is associated with significant morbidity, increased hospitalizations, reduced survival, and increased health care costs. Recommended preventive strategies such as administration of intravenous antibiotics before implantation are well-recognized. Uncertainties have remained about the role of various preventive, diagnostic, and treatment measures such as skin antiseptics, pocket antibiotic solutions, antibacterial envelopes, prolonged antibiotics post-implantation, and others. When compared with previous guidelines or consensus statements, the present consensus document gives guidance on the use of novel device alternatives, novel oral anticoagulants, antibacterial envelopes, prolonged antibiotics post-implantation, as well as definitions on minimum quality requirements for centres and operators and volumes. The recognition that an international consensus document focused on management of CIED infections is lacking, the dissemination of results from new important randomized trials focusing on prevention of CIED infections, and observed divergences in managing device-related infections as found in an European Heart Rhythm Association worldwide survey, provided a strong incentive for a Novel 2019 International State-of-the-art Consensus document on risk assessment, prevention, diagnosis, and treatment of CIED infections.

PET/CT Imaging for Personalized Management of Infectious Diseases

Positron emission tomography combined with computed tomography (PET/CT) is a nuclear imaging technique which is increasingly being used in infectious diseases. Because infection foci often consume more glucose than surrounding tissue, most infections can be diagnosed with PET/CT using 2-deoxy-2-[18F]fluoro-D-glucose (FDG), an analogue of glucose labeled with Fluorine-18. In this review, we discuss common infectious diseases in which FDG-PET/CT is currently applied including bloodstream infection of unknown origin, infective endocarditis, vascular graft infection, spondylodiscitis, and cyst infections. Next, we highlight the latest developments within the field of PET/CT, including total body PET/CT, use of novel PET radiotracers, and potential future applications of PET/CT that will likely lead to increased capabilities for patient-tailored treatment of infectious diseases.

FDG-PET/CT in Fever of Unknown Origin, Bacteremia, and Febrile Neutropenia

Fever of unknown origin, bacteremia, and febrile neutropenia are diagnostic challenges. FDG-PET/CT is a well-established modality in infection imaging and the literature increasingly supports its use in these settings. In fever of unknown origin, FDG-PET/CT is helpful, but diagnostic yield depends on patient selection and inflammatory markers. In bacteremia, FDG-PET/CT is cost-effective, reduces morbidity and mortality, and impacts treatment strategy. Although use of FDG-PET/CT in these domains is not established as part of a definitive diagnostic strategy, FDG-PET/CT may help establish final diagnosis in a difficult population and should be considered early in the diagnostic process.

Diagnostic Performance of 18F-FDG PET/CT in Native Valve Endocarditis: Systematic Review and Bivariate Meta-Analysis

BACKGROUND

Infectious endocarditis is a life-threatening disease, requiring prompt and accurate diagnosis. The aim of this article is to perform a systematic review and meta-analysis of the literature to estimate the performance of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for the diagnosis of native valve endocarditis (NVE).

METHODS

Selected articles evaluating the diagnostic accuracy of 18F-FDG PET/CT in patients with suspected NVE, resulting from a comprehensive literature search through the PubMed/MEDLINE and Cochrane library databases until April 2020, were included for the systematic review and meta-analysis.

RESULTS

Seven studies (351 episodes of suspected NVE) were included. 18F-FDG PET/CT yielded a pooled sensitivity of 36.3% and a pooled specificity of 99.1% for the diagnosis of NVE. The pooled positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 8.3, 0.6, and 15.3, respectively. The sensitivity increased using contemporary PET/CT device with state-of-the-art patient preparation as well as innovative image acquisitions or adding the results of 18F-FDG PET/CT in a multimodality strategy.

CONCLUSIONS

In our systematic review and meta-analysis, 18F-FDG PET/CT yielded a poor pooled sensitivity with an otherwise excellent pooled specificity for the diagnosis of NVE; however, several factors may increase the sensitivity without affecting the specificity and these factors should be better evaluated in future studies.

Integration of FDG-PET/CT in the diagnostic workup for Staphylococcus aureus bacteremia: a prospective interventional matched-cohort study

BACKGROUND

Staphylococcus aureus bacteremia (SAB) is uniquely characterized by focal pyogenic complications that might not be apparent clinically. We investigated the benefit of adding FDG-PET/CT in the workup of patients with SAB.

METHODS

Matched-cohort study. Patients with SAB (intervention group) were prospectively recruited to undergo FDG-PET/CT 7-14 days after diagnosis. Treatment was directed by FDG-PET/CT findings. Clinical outcomes were compared to a control group of patients with SAB who had not undergone FDG-PET/CT, matched by age, Charlson score, methicillin susceptibility and survival duration to FDG-PET/CT. The primary outcome was 90-day mortality. Residual confounding was controlled through regression analyses.

RESULTS

During the study period 149 patients with 151 separate episodes of SAB underwent FDG-PET/CT and were compared to 150 matched patients with 151 SAB episodes. Patients in the intervention group acquired infections more frequently in the community, had less frequently solid malignancies and more frequently high-risk SAB. Ninety-day mortality in the intervention group was significantly lower than in the control group [21/151 (13.9%) vs. 43/151 (28.5%), p=0.002]. The difference remained significant in a subgroup analysis of patients with community-onset infections without malignancy and among patients with low-risk SAB. Controlling for other risk factors for mortality, FDG-PET/CT performance among all patients was independently associated with lower mortality, odds ratio 0.39, 95% confidence interval 0.18-0.84. Patients in the intervention group had longer duration of treatment and more focus control procedures performed compared to the control group.

CONCLUSION

FDG-PET/CT in patients with SAB seems to improve survival through guidance of treatment duration and co-interventions.

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.

Imaging infective endocarditis: Adherence to a diagnostic flowchart and direct comparison of imaging techniques

BACKGROUND

Multimodality imaging is recommended to diagnose infective endocarditis. Value of additional imaging to echocardiography in patients selected by a previously proposed flowchart has not been evaluated.

METHODS

An observational single-center study was performed. Adult patients suspected of endocarditis/device infection were prospectively and consecutively enrolled from March 2016 to August 2017. Adherence to a diagnostic imaging-in-endocarditis-flowchart was evaluated in 176 patients. Imaging techniques were compared head-to-head in 46 patients receiving echocardiography (transthoracic plus transesophageal), multi-detector computed tomography angiography (MDCTA), and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET/CT).

RESULTS

69% of patients (121/176) adhered to the flowchart. Sensitivity of echocardiography, MDCTA, FDG-PET/CT in patients without prosthesis was 71%, 57%, 29% (86% when combined), while specificity was 100%, 75%, 100%, respectively. Sensitivity in patients with prosthesis was 75%, 75%, 83%, respectively (100% when combined), while specificity was 86% for all three modalities. Echocardiography performed best in the assessment of vegetations, morphological valve abnormalities/dehiscence, septum defects, and fistula formation. MDCTA performed best in the assessment of abscesses and ventricular assist device infection. FDG-PET/CT performed best in the assessment of cardiac device infection, extracardiac infectious foci, and alternative diagnoses.

CONCLUSIONS

This study demonstrates that the evaluated imaging-in-endocarditis-flowchart is applicable in daily clinical practice. Echocardiography, MDCTA, and FDG-PET/CT provide relevant complementary diagnostic information, particularly in patients with intracardiac prosthetic material.

Access, knowledge and experience with fluorodeoxyglucose positron emission tomography/computed tomography in infection management: a survey of Australia and New Zealand infectious diseases physicians and microbiologists

BACKGROUND

Despite fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) being funded only for staging and restaging of some malignancies in Australia, there is evidence of benefit of FDG-PET/CT for infection indications such as pyrexia of unknown origin (PUO), prolonged neutropenic fever (NF) and prosthetic device infection.

AIM

To evaluate the current knowledge, utilisation of and gaps in access to FDG-PET/CT for infectious indications by Australasian infectious diseases (ID) physicians and microbiologists.

METHODS

An online survey was administered to ID and microbiology doctors practising in adult medicine in Australia and New Zealand through two established email networks. Using targeted questions and case-based examples, multiple themes were explored, including access to FDG-PET/CT, use and perceived benefit of FDG-PET/CT in diagnosis and monitoring of non-malignant conditions such as NF and PUO, and barriers to clinical use of FDG-PET/CT.

RESULTS

A response was received from 120 participants across all states and territories. Onsite and offsite FDG-PET/CT access was 63% and 31% respectively. Eighty-six percent reported using FDG-PET/CT for one or more infection indications and all had found it clinically useful, with common indications being PUO, prosthetic device infections and use in the immunocompromised host for prolonged NF and invasive fungal infection. Thirty-eight percent reported barriers in accessing FDG-PET/CT for infection indications and 76% would utilise FDG-PET/CT more frequently if funding existed for infection indications.

CONCLUSION

Access to FDG-PET/CT in Australia and New Zealand is modest and is limited by lack of reimbursement for infection indications. There is discrepancy between recognised ID indications for FDG-PET/CT and funded indications.

Pneumococcal Disease: A Systematic Review of Health Utilities, Resource Use, Costs, and Economic Evaluations of Interventions

BACKGROUND

Pneumococcal diseases cause substantial mortality, morbidity, and economic burden. Evidence on data inputs for economic evaluations of interventions targeting pneumococcal disease is critical.

OBJECTIVES

To summarize evidence on resource use, costs, health utilities, and cost-effectiveness for pneumococcal disease and associated interventions to inform future economic analyses.

METHODS

We searched MEDLINE, Embase, Web of Science, CINAHL, PsycINFO, EconLit, and Cochrane databases for peer-reviewed studies in English on pneumococcal disease that reported health utilities using direct or indirect valuation methods, resource use, costs, or cost-effectiveness of intervention programs, and summarized the evidence descriptively.

RESULTS

We included 383 studies: 9 reporting health utilities, 131 resource use, 160 economic costs of pneumococcal disease, 95 both resource use and costs, and 178 economic evaluations of pneumococcal intervention programs. Health state utility values ranged from 0 to 1 for both meningitis and otitis media and from 0.3 to 0.7 for both pneumonia and sepsis. Hospitalization was shortest for otitis media (range: 0.1-5 days) and longest for sepsis/septicemia (6-48). The main categories of costs reported were drugs, hospitalization, and household or employer costs. Resource use was reported in hospital length of stay and number of contacts with general practitioners. Costs and resource use significantly varied among population ages, disease conditions, and settings. Current vaccination programs for both adults and children, antibiotic use and outreach programs to promote vaccination, early disease detection, and educational programs are cost-effective in most countries.

CONCLUSION

This study has generated a comprehensive repository of health economic evidence on pneumococcal disease that can be used to inform future economic evaluations of pneumococcal disease intervention programs.

FDG PET/CT of Infection: Should It Replace Labeled Leukocyte Scintigraphy of Inpatients?

OBJECTIVE. The purpose of this study was to compare the sensitivity, specificity, and helpfulness to referring clinicians of labeled leukocyte scintigraphy versus FDG PET/CT in inpatients with suspected infection. MATERIALS AND METHODS. In this retrospective study, labeled leukocyte scintigraphy and FDG PET/CT examinations performed from 2009 to 2017 for suspected infection in inpatients were identified. Sensitivity, specificity, and helpfulness of PET/CT versus labeled leukocyte scintigraphy were calculated by means of a mixed generalized linear model. Number of yearly tests and radiopharmaceutical costs were also assessed. RESULTS. Fifty-seven patients (30 men, 27 women; median age, 65 years; range, 21-91 years) underwent whole-body labeled leukocyte scintigraphy. Forty-two patients (30 male patients, 12 female patients; median age, 62.5 years; range, 12-91 years) underwent PET/CT for suspected infection. Labeled leukocyte scintigraphy was 66.7% sensitive, whereas the sensitivity of PET/CT was 89.7% (p = 0.0485). The higher sensitivity of PET/CT did not come at a cost to specificity, which was 73.3% as opposed to 76.9% for labeled leukocyte scintigraphy (p = 0.8050). The odds of a positive study being helpful increased 4.6-fold for PET/CT versus labeled leukocyte scintigraphy (p = 0.0412). From 2009 to 2011, 33 labeled leukocyte scintigraphic examinations were performed versus two PET/CT examinations; and from 2012 to 2014, 16 labeled leukocyte scintigraphic versus 22 PET/CT examinations; from 2015 to 2017, eight labeled leukocyte scintigraphic versus 18 PET/CT examinations. The cost of labeled leukocytes increased between 2009 and 2017, but that of FDG decreased. By 2017, a labeled leukocyte radiopharmaceutical dose was approximately 10 times the cost of an FDG dose. CONCLUSION. PET/CT was more sensitive than and as specific as labeled leukocyte scintigraphy for identifying a source of infection in inpatients, and it was more helpful to referring clinicians. Use of PET/CT increased over time and was associated with substantial savings in radiopharmaceutical cost.

Diagnostic Performance of 18F-FDG PET/CT in Infectious and Inflammatory Diseases according to Published Meta-Analyses

Purpose

To date, several meta-analyses have reported data about the diagnostic performance of ¹⁸F-FDG PET/CT in infectious and inflammatory diseases. This article aims to summarize the published evidence-based data about the diagnostic performance of ¹⁸F-FDG PET/CT in this setting.

Methods

A comprehensive computer literature search of meta-analyses published in PubMed/MEDLINE and Cochrane library database from January 2009 through December 2018 and regarding the diagnostic performance of ¹⁸F-FDG PET/CT in infectious and inflammatory diseases was carried out. This combination of key words was used: (i) “PET” OR “positron emission tomography” OR “FDG” OR “fluorodeoxyglucose” AND (ii) meta-analysis. Only records on inflammatory or infectious diseases were selected.

Results

The diagnostic performance of ¹⁸F-FDG PET/CT in detecting inflammatory and infectious diseases has been summarized taking into account 36 meta-analyses published in the literature. Evidence-based data demonstrated good diagnostic performance of ¹⁸F-FDG PET/CT for several inflammatory and infectious diseases, in particular cardiovascular infectious and inflammatory diseases and some musculoskeletal infections.

Conclusions

Evidence-based data about the diagnostic performance of ¹⁸F-FDG PET/CT in infectious and inflammatory diseases are increasing, with good diagnostic performance of this imaging method for some indications. More prospective multicenter studies and cost-effective analyses are warranted.

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.

Mortality in patients with high risk Staphylococcus aureus bacteremia undergoing or not PET-CT: A single center experience

BACKGROUND

Staphylococcus aureus bacteremia (SAB) is associated with significant morbidity and mortality. Previous studies had shown that PET/CT can be helpfull in the management of SAB, leading to reduction of mortality. Factors associated with increased or reduced mortality are not well known. Our objective was to analyze mortality in high risk SAB patients undergoing PET/CT and to identify factors associated with mortality rate.

MATERIALS AND METHODS

We performed a retrospective study and reviewed all cases of high risk adult SAB between 2014 and 2017. We analyzed medical records and mortality at 30 days and 90 days and 1 year.

RESULTS

A total of 102 patients were included in whom 48 undergone PET/CT. Metastatic foci was identified in 45.8% of cases (22/48). The overall mortality rate was 31.4% (32/102). The mortality rate was 16.6% (8/48) and 44.4% (24/54) in patients undergoing or not PET/CT respectively (P = 0.002). There was a signicantly difference in mortality rate at 30 days (P = 0.001), 90 days (P = 0.004) and one at 1 year (P = 0.002) between patients undergoing or not PET/CT respectively. In multivariate analysis only 18-FDGPET/CT, kidney failure and bacteremia of unknown origin were the 3 mains factors modifying mortality in patients with high risk SAB.

CONCLUSION

In our study mortality rate was reduced in high risk SAB patients undergoing PET/CT. kidney failure and bacteremia of unknown origin were other factors associtated with high mortality. Our study confirm that PET/CT is a usefull tool in the management of SAB.

Clinical value of FDG-PET/CT in bacteremia of unknown origin with catalase-negative gram-positive cocci or Staphylococcus aureus

INTRODUCTION

Bacteremia is associated with high mortality, especially when the site of infection is unknown. While conventional imaging usually focus on specific body parts, FDG-PET/CT visualizes hypermetabolic foci throughout the body.

PURPOSE

To investigate the ability of FDG/PET-CT to detect the site of infection and its clinical impact in bacteremia of unknown origin with catalase-negative Gram-positive cocci (excluding pneumococci and enterococci) or Staphylococcus aureus (BUOCSA).

METHODS

We retrospectively identified 157 patients with 165 episodes of BUOCSA, who subsequently underwent FDG-PET/CT. Data were collected from medical records. Decision regarding important sites of infection in patients with bacteremia was based on the entire patient course and served as reference diagnosis for comparison with FDG-PET/CT findings. FDG-PET/CT was considered to have high clinical impact if it correctly revealed site(s) of infection in areas not assessed by other imaging modalities or if other imaging modalities were negative/equivocal in these areas, or if it established a new clinically relevant diagnosis, and/or led to change in antimicrobial treatment.

RESULTS

FDG-PET/CT detected sites of infection in 56.4% of cases and had high clinical impact in 47.3%. It was the first imaging modality to identify sites of infection in 41.1% bacteremia cases, led to change of antimicrobial therapy in 14.7%, and established a new diagnosis unrelated to bacteremia in 9.8%. Detection rate and clinical impact were not significantly influenced by duration of antimicrobial treatment preceding FDG-PET/CT, days from suspicion of bacteremia to FDG-PET/CT-scan, type of bacteremia, or cancer.

CONCLUSION

FDG-PET/CT appears clinically useful in BUOCSA. Prospective studies are warranted for confirmation.

FDG-PET/CT for Detecting an Infection Focus in Patients With Bloodstream Infection: Factors Affecting Diagnostic Yield

PURPOSE

To investigate the diagnostic performance of F-fluoro-2-deoxy-D-glucose (FDG) PET/ CT for the detection of an infection focus in patients with a bloodstream infection (BSI) and to identify factors influencing the diagnostic yield of FDG-PET/CT.

METHODS

This retrospective single-center study included 185 consecutive patients with a BSI who underwent an FDG-PET/CT scan for the detection of an infection focus between 2010 and 2017. The final diagnosis at hospital discharge was used as reference standard. Diagnostic performance of FDG-PET/CT for the detection of an infection focus was assessed, and logistic regression analyses were performed to identify factors associated with FDG-PET/CT yield.

RESULTS

An infection focus was identified on FDG-PET/CT in 120 (64.8%) of 185 patients. FDG-PET/CT achieved a sensitivity of 80.2%, specificity of 79.6%, positive predictive value of 90.8%, and a negative predictive value of 61.4% for detecting an infection focus in patients with a BSI. Blood cultures positive for enterococci (odds ratio, 0.14; P = 0.019) and days of antibiotic treatment before FDG-PET/CT (odds ratio, 0.94 per day increase; P = 0.014) were statistically significant independent predictors of a lower odds of detecting an infection focus on FDG-PET/CT. In patients who received antibiotics for less than 7 days before FDG-PET/CT, an infection focus was found in 71% (56/79). In patients who received antibiotics for 8 to 14 days before FDG-PET/CT, an infection focus was found in 52% (22/42). After 15 to 21 days of antibiotic treatment, an infection focus was found in 61% (8/13), and for 22 days or more, this declined to 38% (5/13).

CONCLUSIONS

FDG-PET/CT is a useful method for detecting an infection focus in patients with BSI. However, longer duration of antibiotic treatment before FDG-PET/CT and bacteremia with enterococci reduce the diagnostic yield of FDG-PET/CT. These factors should be taken into account when considering an FDG-PET/CT scan for this indication.

18F-FDG PET/CT-Guided Treatment Duration in Patients with High-Risk Staphylococcus Aureus Bacteremia: A Proof of Principle

Current guidelines recommend intravenous antibiotic therapy for at least 4 wk in patients with high-risk Staphylococcus aureus bacteremia (SAB), because of the risk for metastatic infection. We evaluated the safety of a shorter duration of treatment in patients with high-risk SAB without signs of metastatic infection at presentation, using standard ¹⁸F-FDG PET/CT and echocardiography. Methods: Retrospective analyses were performed of patients with SAB admitted between 2013 and 2017 in 2 medical centers. Patients with risk factors for complicated bacteremia (community acquisition, persistently positive blood cultures, >72 h of fever, or foreign body materials present), a normal echocardiography result, and ¹⁸F-FDG PET/CT without signs of metastatic infection were included (cases) and compared with patients with uncomplicated bacteremia (absence of any of the risk factors and no known metastatic disease, controls). Primary outcomes were 3-mo SAB-specific mortality rate and recurrent infection. The secondary outcome was overall mortality. Results: We included 36 cases and 40 controls. Both groups had a similar treatment duration (15.9 vs. 15.4 d). No deaths occurred as a consequence of SAB in the cases, compared with 1 in the control group. One relapse occurred in the case group and 2 in the control group. Overall mortality did not differ between the groups (19.4% vs. 15.0%, P = 0.64). Conclusion: This study suggests that intravenous treatment for 2 wk in high-risk patients with SAB without endocarditis and absence of metastatic infection on ¹⁸F-FDG PET/CT is safe. A diagnostic-driven approach using ¹⁸F-FDG PET/CT to determine treatment duration in high-risk SAB seems feasible and allows tailoring treatment to individual patients.

99mTc-HMPAO-labeled leukocyte SPECT/CT and transthoracic echocardiography diagnostic value in infective endocarditis

Infective endocarditis (IE) is a life-threatening disease, establishing a diagnosis is often challenging. The aim of this prospective study was to evaluate and compare the diagnostic performance of the combined use of single photon emission tomography and computed tomography with technetium99m-hexamethylpropyleneamineoxime—labeled leukocytes (99mTc-HMPAO-SPECT/CT) with transthoracic echocardiography (TTE) in patients with suspected IE. We enrolled 40 consecutive patients (12 females, 28 males, mean age: 58.6 ± 18) with suspected IE in the years 2015–2016. All patients underwent clinical evaluation, TTE and 99mTc-HMPAO-SPECT/CT for the assessment of lesions typical for IE. Scans were evaluated for the presence and location of increased radioactivity foci, corresponding to the accumulation of radiolabeled leukocytes in inflammatory lesions. After 6 months, the patients were re-evaluated clinically and with TTE. Final IE diagnosis was established in 14 (35%) patients. Lesions typical for IE were shown in 28 (70%) TTEs and 16 (40%) 99mTc-HMPAO-SPECT/CTs. The latter tests were characterized by 90% accuracy, 93% sensitivity, 88% specificity, 96% negative predictive value (NPV), 81% positive predictive value (PPV). TTE demonstrated 60% accuracy, 93% sensitivity, 42% specificity, 92% NPV, and 46% PPV. 99mTc-HMPAO-SPECT/CT was characterized by a lower number of false-positive results compared to TTE (3 vs. 15). In patients with suspected IE, 99mTc-HMPAO-SPECT/CT yields a smaller number of false-positive results, significantly higher diagnostic accuracy, specificity and PPV than TTE. It helps to differentiate IE infectious and sterile echocardiographic lesions and reduces by 27% the number of misdiagnosed IE classified in the ‘possible IE’ category by modified Duke Criteria.

Sonication of heart valves detects more bacteria in infective endocarditis

Optimal antimicrobial treatment of infective endocarditis requires identification and susceptibility patterns of pathogens. Sonication of explanted heart valves could increase the identification and culture of pathogens, as shown in prosthetic joint and pacemaker/ICD infections. We tested 26 explanted heart valves from 20 patients with active definite endocarditis for added diagnostic value of sonication to the standard microbiological workup in a prospective diagnostic proof of concept study. Two sonication protocols (broth enrichment vs. centrifugation) were compared in an additional 35 negative control valves for contamination rates. We selected sonication/centrifugation based on acceptable false positive rates (11.4%; 4/35). Sonication/enrichment yielded many false positive results in negative controls (28.6%; 10/35), mainly Propionibacterium acnes (next-generation sequencing excluded technical problems). Compared to direct culture only, adding sonication/centrifugation (including molecular testing) significantly increased the diagnostic yield from 6/26 to 17/26 valves (p = 0.003). Most importantly, culture positives almost doubled (from 6 to 10), providing unique quantitative information about antimicrobial susceptibility. Even if direct molecular testing was added to the standard workup, sonication/centrifugation provided additional diagnostic information in a significant number of valves (8/26; 31%; p = 0.013). We concluded that sonication/centrifugation added relevant diagnostic information in the workup of heart valves with infective endocarditis, with acceptable contamination rates.

C-reactive protein levels can predict positive 18F-FDG PET/CT findings that lead to management changes in patients with bacteremia

BACKGROUND/PURPOSE

Bacteremia portends high rates of morbidity and mortality. Although ¹⁸F-fluorodeoxyglucose positron emission tomography and computed tomography (¹⁸F-FDG PET/CT) imaging has clinical value in assessing fever of unknown origin, its usefulness in bacteremia has not been entirely elucidated. We therefore designed the current single-center retrospective study to investigate 1) the clinical value of ¹⁸F-FDG PET/CT imaging in assessing bacteremia and 2) the association between laboratory data and imaging findings.

METHODS

We examined 102 patients with bacteremia who had undergone ¹⁸F-FDG PET/CT imaging. The patients' clinical and laboratory data were reviewed and analyzed in relation to ¹⁸F-FDG PET/CT findings. Patients showing positive results underwent quantitative measurements of ¹⁸F-FDG uptake.

RESULTS

Positive ¹⁸F-FDG PET/CT findings were identified in 74 (72.5%) patients, and 40 (54.1%) underwent modified treatment or management because of the imaging results (p = 0.003). Positive ¹⁸F-FDG PET/CT findings were significantly associated with higher white blood cell (WBC) counts and C-reactive protein (CRP) levels (p = 0.012 and < 0.001, respectively). Notably, CRP levels accurately predicted (area under curve = 0.752; p < 0.001) positive ¹⁸F-FDG PET/CT findings (optimal cut-off point: 54.025 mg/L).

CONCLUSION

A majority (54.1%, n = 40) of the patients with positive ¹⁸F-FDG PET/CT results underwent treatment modifications; they accounted for most cases (87%) of management changes in our cohort. Leukocytosis and increased CRP levels are significantly associated with positive ¹⁸F-FDG PET/CT findings in patients with bacteremia. CRP levels >54.025 mg/L were accurate predictors of positive ¹⁸F-FDG PET/CT results.

Long-term Staphylococcus aureus decolonization in patients on home parenteral nutrition: study protocol for a randomized multicenter trial

Background

Patients with long-term intestinal failure are usually treated by means of home parenteral nutrition (HPN) where they administer their nutritional formulation intravenously via a central venous access device (mostly a catheter). This implies that such patients are exposed to a lifelong risk of developing Staphylococcus aureus bacteremia (SAB). SAB poses a threat to both catheter and patient survival and may lead to frequent hospitalization and a permanent loss of vascular access. In other clinical settings, S. aureus carriage eradication has been proven effective in the prevention of S. aureus infections. Unfortunately, there is a complete lack of evidence in HPN support on the most effective and safe S. aureus decolonization strategy in S. aureus carriers. We hypothesized that long-term S. aureus decolonization in HPN patients can only be effective if it is aimed at the whole body (nasal and extra-nasal) and is given chronically or repeatedly on indication. Besides this, we believe that S. aureus carriage among caregivers, who are in close contact with the patient, are of great importance in the S. aureus transmission routes.

Methods/design

The CARRIER trial is a randomized, open-label, multicenter clinical trial in Dutch and Danish hospitals that treat patients on HPN. A total of 138 adult HPN patients carrying S. aureus will be randomly assigned to a search and destroy (SD) strategy, a quick and short, systemic antibiotic treatment, or a continuous suppression (CS) strategy, a repeated chronic topical antibiotic treatment. The primary outcome measure is the proportion of patients in whom S. aureus is totally eradicated during a 1-year period. Secondary outcomes are time to successful eradication, long-term antimicrobial resistance, adverse events, patient compliance, incidence of (S. aureus) infections, catheter removals, mortality rates, S. aureus transmission routes, quality of life, and health care costs.

Discussion

The CARRIER trial is designed to identify the most safe and effective long-term S. aureus carriage decolonization strategy in HPN patients. This will eventually lead to a better understanding of long-term S. aureus decolonization treatments in general. The results of this study will have a great impact on our daily clinical practice, which eventually may result in less S. aureus-related infections.

Trial registration

ClinicalTrials.gov; NCT03173053. Registered on 1 June 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2732-2) contains supplementary material, which is available to authorized users.

Prosthetic valve endocarditis: positron emission tomography/computed tomography as a new golden grail

Prosthetic valve endocarditis (PVE) is a serious infection with potentially fatal consequences. Early detection is crucial for successful management and outcome. The diagnosis of PVE is challenging and is based on the Duke criteria (DC) in which echocardiography plays a crucial role. However, transthoracic and transoesophageal echocardiography have less diagnostic value in PVE compared to native valve endocarditis. Combined computed tomography and fluorodeoxyglucose positron emission is a new technique providing improved diagnostic accuracy in PVE. This paper presents a case and reviews on the role of positron emission tomography/computed tomography in PVE.

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.

The Value of 18F-FDG PET/CT in Diagnosis and During Follow-up in 273 Patients with Chronic Q Fever

In 1%-5% of all acute Q fever infections, chronic Q fever develops, mostly manifesting as endocarditis, infected aneurysms, or infected vascular prostheses. In this study, we investigated the diagnostic value of ¹⁸F-FDG PET/CT in chronic Q fever at diagnosis and during follow-up. Methods: All adult Dutch patients suspected of chronic Q fever who were diagnosed since 2007 were retrospectively included until March 2015, when at least one ¹⁸F-FDG PET/CT scan was obtained. Clinical data and results from ¹⁸F-FDG PET/CT at diagnosis and during follow-up were collected. ¹⁸F-FDG PET/CT scans were prospectively reevaluated by 3 nuclear medicine physicians using a structured scoring system. Results: In total, 273 patients with possible, probable, or proven chronic Q fever were included. Of all ¹⁸F-FDG PET/CT scans performed at diagnosis, 13.5% led to a change in diagnosis. Q fever-related mortality rate in patients with and without vascular infection based on ¹⁸F-FDG PET/CT was 23.8% and 2.1%, respectively (P = 0.001). When ¹⁸F-FDG PET/CT was added as a major criterion to the modified Duke criteria, 17 patients (1.9-fold increase) had definite endocarditis. At diagnosis, 19.6% of ¹⁸F-FDG PET/CT scans led to treatment modification. During follow-up, 57.3% of ¹⁸F-FDG PET/CT scans resulted in treatment modification. Conclusion:¹⁸F-FDG PET/CT is a valuable technique in diagnosis of chronic Q fever and during follow-up, often leading to a change in diagnosis or treatment modification and providing important prognostic information on patient survival.

18F-FDG PET/CT Optimizes Treatment in Staphylococcus Aureus Bacteremia and Is Associated with Reduced Mortality

Metastatic infection is an important complication of Staphylococcus aureus bacteremia (SAB). Early diagnosis of metastatic infection is crucial, because specific treatment is required. However, metastatic infection can be asymptomatic and difficult to detect. In this study, we investigated the role of ¹⁸F-FDG PET/CT in patients with SAB for detection of metastatic infection and its consequences for treatment and outcome. Methods: All patients with SAB at Radboud University Medical Center were included between January 2013 and April 2016. Clinical data and results of ¹⁸F-FDG PET/CT and other imaging techniques, including echocardiography, were collected. Primary outcomes were newly diagnosed metastatic infection by ¹⁸F-FDG PET/CT, subsequent treatment modifications, and patient outcome. Results: A total of 184 patients were included, and ¹⁸F-FDG PET/CT was performed in 105 patients, of whom 99 had a high-risk bacteremia. ¹⁸F-FDG PET/CT detected metastatic infectious foci in 73.7% of these high-risk patients. In 71.2% of patients with metastatic infection, no signs and symptoms suggesting metastatic complications were present before ¹⁸F-FDG PET/CT was performed. ¹⁸F-FDG PET/CT led to a total of 104 treatment modifications in 74 patients. Three-month mortality was higher in high-risk bacteremia patients without ¹⁸F-FDG PET/CT performed than in those in whom ¹⁸F-FDG PET/CT was performed (32.7% vs. 12.4%, P = 0.003). In multivariate analysis, ¹⁸F-FDG PET/CT was the only factor independently associated with reduced mortality (P = 0.005; odds ratio, 0.204; 95% confidence interval, 0.066-0.624). A higher comorbidity score was independently associated with increased mortality (P = 0.003; odds ratio, 1.254; 95% confidence interval, 1.078-1.457). Conclusion:¹⁸F-FDG PET/CT is a valuable technique for early detection of metastatic infectious foci, often leading to treatment modification. Performing ¹⁸F-FDG PET/CT is associated with significantly reduced 3-mo mortality.

Role of PET/CT in Workup of Fever without a Source

Fever without source is a febrile illness without localizing signs or initial obvious cause. Early workup will often include chest radiography and computed tomography (CT) of the abdomen and pelvis, with or without CT of the chest. To evaluate localizing signs or symptoms or to further evaluate findings from initial studies, targeted imaging according to body part can be performed by using radiography, ultrasonography, CT, or magnetic resonance (MR) imaging. Nuclear medicine studies can provide imaging of the whole body and may be helpful when the clinical and conventional imaging workup findings are negative or equivocal in identifying a source of fever. Nuclear medicine studies can be used to detect pathologic changes early in a disease course, even in the absence of an anatomic abnormality. Gallium 67 scintigraphy, indium 111- and technetium 99m-labeled leukocyte scintigraphy, and fluorine 18 fluorodeoxyglucose positron emission tomography (PET)/CT studies are all useful in the evaluation of fever, but the radiopharmaceutical cost for PET/CT is much lower than that for radiolabeled leukocyte studies. The increased use of bundled payments for inpatient admissions requires updated cost evaluations for the preferred nuclear medicine study. For inpatients in whom the findings from the initial clinical workup and imaging studies are nondiagnostic, PET/CT examination may be preferable to radiolabeled leukocyte studies because of its high sensitivity and lower cost. Negative findings at PET/CT can be helpful in excluding a suspected site of infection, and positive findings at PET/CT can be helpful in confirming a suspected site of infection or in identifying an unexpected cause of fever. (©)RSNA, 2016.

The clinical utility of FDG PET/CT among solid organ transplant recipients suspected of malignancy or infection

PURPOSE

Solid organ transplant (SOT) recipients are at high risk of developing infections and malignancies. 18F-FDG PET/CT may enable timely detection of these diseases and help to ensure early intervention. We aimed to describe the clinical utility of FDG PET/CT in consecutive, diagnostic unresolved SOT recipients transplanted from January 2004 to May 2015.

METHODS

Recipients with a post-transplant FDG PET/CT performed as part of diagnostic work-up were included. Detailed chart reviews were done to extract relevant clinical information and determine the final diagnosis related to the FDG PET/CT. Based on á priori defined criteria and the final diagnosis, results from each scan were classified as true or false, and diagnostic values determined.

RESULTS

Among the 1,814 recipients in the cohort, 145 had an FDG PET/CT performed; 122 under the indication of diagnostically unresolved symptoms with a suspicion of malignancy or infection. The remaining (N = 23) had an FDG PET/CT to follow-up on a known disease or to stage a known malignancy. The 122 recipients underwent a total of 133 FDG PET/CT scans performed for a suspected malignancy (66 %) or an infection (34 %). Sensitivity, specificity, and positive and negative predictive values of the FDG PET/CT in diagnosing these conditions were 97, 84, 87, and 96 %, respectively.

CONCLUSION

FDG PET/CT is an accurate diagnostic tool for the work-up of diagnostic unresolved SOT recipients suspected of malignancy or infection. The high sensitivity and NPV underlines the potential usefulness of PET/CT for excluding malignancy or focal infections in this often complex clinical situation.

Septic pulmonary emboli detected by 18F-FDG PET/CT in children with S. aureus catheter-related bacteremia

PURPOSE

The role of ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET/CT) in the diagnosis of metastatic infectious foci in children with catheter-related blood stream infection has been hardly studied, although some authors have reported it benefit in the screening of metastatic foci in adult population. Septic pulmonary emboli are among the most difficult to identify, because many cases do not present pulmonary complaints or abnormal chest radiography. However, diagnosis of these foci has important therapeutic consequences. The purpose of this article is to describe the role of ¹⁸F-FDG PET/CT in the diagnosis of septic pulmonary embolism in children with S. aureus catheter-related bacteremia.

METHODS

We report 3 children with S. aureus catheter-related bacteremia and normal chest X-ray at admission, in whom ¹⁸F-FDG PET/CT led to the diagnosis of unsuspected septic pulmonary emboli, with an impact on clinical management.

RESULTS

All patients had hemophilia and implantable venous access ports and presented with fever and normal lung auscultation. Only 1 reported non-specific symptoms (undifferentiated left chest pain). All patients had normal chest X-ray on admission. Catheters were removed within 48 h after admission in 2 cases, and 5 days after admission in the last case, subsiding fever. In 2 children, paired blood cultures were not able to identify bacteremia. However, in all cases catheter tip and subcutaneous port cultures yielded S. aureus and PET/CT detected unsuspected pulmonary metastatic emboli.

CONCLUSIONS

¹⁸F-FDG PET/CT should be considered as a useful tool to diagnose septic pulmonary embolism in S. aureus catheter-related bacteremia, especially if conventional diagnostic imaging techniques have failed to reveal possible metastatic foci. Further studies are needed to clarify the usefulness of PET/CT performance in children with CRBSI.

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.

A comparison of the diagnostic value of MRI and 18F-FDG-PET/CT in suspected spondylodiscitis

Purpose

The purpose of this study was to evaluate the diagnostic value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT scan) and magnetic resonance imaging (MRI) in diagnosing spondylodiscitis and its complications, such as epidural and paraspinal abscesses.

Methods

From January 2006 to August 2013 patients with a clinical suspicion of spondylodiscitis, with an infection, or with fever of unknown origin were retrospectively included if ¹⁸F-FDG-PET/CT and MRI of the spine were performed within a 2-week time span. Imaging results were compared to the final clinical diagnosis and follow-up data were collected.

Results

Sixty-eight patients were included of whom 49 patients were diagnosed with spondylodiscitis. MRI showed an overall sensitivity of 67 % and specificity of 84 %. Diagnostic accuracy was 58 %, when MRI was performed within 2 weeks after the start of symptoms and improved to 82 %, when performed more than 2 weeks after onset of symptoms. ¹⁸F-FDG-PET/CT showed a sensitivity of 96 % and a specificity of 95 %, with no relation to the interval between the scan and the start of symptoms.

Conclusions

As compared to MRI, ¹⁸F-FDG-PET/CT has superior diagnostic value for detecting early spondylodiscitis. After 2 weeks both techniques perform similarly.

Assessment of Therapy Response by FDG PET in Infection and Inflammation

Positron emission tomography (PET) is a well-known imaging modality in assessing the treatment response to chemotherapy or radiotherapy in various malignancies. A systematic review of the literature reveals a few publications reporting evaluation of the treatment response in benign conditions using PET/computed tomography. PET holds a promising future role in the follow-up of inflammatory or infectious diseases. In this article, [(18)F]Fluorodeoxyglucose PET as a tool in the evaluation, treatment, and follow-up of infectious and inflammatory diseases is discussed.

PET-Based Personalized Management of Infectious and Inflammatory Disorders

It is challenging to diagnose and manage infectious and inflammatory diseases; symptoms are relatively nonspecific, the disease patterns are often systemic. Imaging is pivotal and fluorodeoxyglucose (FDG)-PET/computed tomography (CT) is increasingly used due to its high sensitivity whole-body approach. At present, the literature is still relatively sparse, but evidence for FDG-PET/CT is mounting in several domains, for example, detecting culprit lesions in systemic infections and inflammations, evaluation of disease extent and therapy monitoring, and many other domains have shown considerable potential, for example, atherosclerosis in systemic inflammation. We believe FDG-PET/CT is becoming a first-line modality for infections and inflammation.