Impact of F-18 FDG PET-CT for the Diagnosis and Management of Infection in JARVIK 2000 Device

Radionuclide Imaging of Infective Endocarditis

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

Diagnostic Accuracy of FDG PET/CT in Suspected LVAD Infections: A Case Series, Systematic Review, and Meta-Analysis

OBJECTIVES

The purpose of this study was to describe our experience with fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography computed tomography (PET/CT) in diagnosing left ventricular assist device (LVAD) infections and perform a meta-analysis of published studies to determine overall diagnostic accuracy.

BACKGROUND

Device-related infections are a common complication of LVADs and are linked to worse outcomes. Diagnosis of LVAD infections remains challenging. FDG PET/CT has demonstrated good diagnostic accuracy in several other infectious conditions.

METHODS

This was a single-center, retrospective case series of FDG PET/CT scans in suspected LVAD infection between September 2015 and February 2018. A systematic review of PubMed from database inception through March 2018 was also conducted to identify additional studies.

RESULTS

Nineteen FDG PET/CT scans were identified for the retrospective case series. The systematic review identified an additional 3 publications, for a total of 4 studies involving 119 scans assessing diagnostic performance. Axial (n = 36) and centrifugal (n = 83) flow LVADs were represented. Pooled sensitivity was 92% (95% confidence interval [CI]: 82% to 97%) and specificity was 83% (95% CI: 24% to 99%) for FDG PET/CT in diagnosing LVAD infections. Summary receiver-operating characteristic curve analysis demonstrated an AUC of 0.94 (95% CI: 0.91 to 0.95).

CONCLUSIONS

FDG PET/CT for suspected LVAD infections demonstrates good diagnostic accuracy, with overall high sensitivity but variable specificity.

In Vitro PET Imaging of a Miniature Ventricular Assist Device

Interactions between the life-sustaining ventricular assist devices and diagnostic therapies must be carefully considered to decrease the risk of inaccurate diagnostic imaging or pump failure.

METHODS

The MVAD(®) pump, currently under investigational use, was tested for interaction with radiotracers in an in vitro flow-loop study. The radiotracers (18)F-sodium fluoride and (18)F-FDG were injected into a closed loop to determine the feasibility of direct imaging of the MVAD(®) pump in a PET scanner.

RESULTS

No real-time changes were observed in pump operation, and there were no statistical differences in pump parameters (power consumption, speed, and estimated flow rate) between the baseline and circulation conditions. In addition, no effect was observed on any external components, including the permissive-action-link controller and the batteries powering the device. Imaging of the internal pump components was possible, with obscuration observed only in the portion of the pump where the spinning impeller is located. Retention of radiotracer in the pump components after circulation was minimal (<1%).

CONCLUSION

PET imaging is an attractive diagnostic tool for patients with a ventricular assist device and may have additional utility outside its current use, detection of infection.

FDG-PET in cardiac infections

Cardiac infections include a group of conditions involving the heart muscle, the pericardium, or the endocardial surface of the heart. Infections can extend to prosthetic material or the leads in case of the implantation of devices. Despite their relative low incidence, these conditions that are associated with high morbidity and mortality involve a relevant burden of diagnostic workup. Early diagnosis is crucial for adequate management of patient, as early treatment improves the prognosis; unfortunately, the clinical manifestations are often nonspecific. Accurate and timely diagnosis typically requires the correlation of imaging findings with laboratory data. (18)F-FDG-PET is a well-established imaging modality for the diagnosis and management of malignancies, and evidence is also increasing regarding its value for assessing infectious and inflammatory diseases. This article summarizes published evidence on the usefulness of (18)F-FDG-PET for the diagnosis of cardiac infections, mainly focused on endocarditis and cardiovascular device infections. Nevertheless, the diagnostic potential of (18)F-FDG-PET in patients with pericarditis and myocarditis is also briefly reviewed, considering the most likely future advances and new perspectives that the use of PET/magnetic resonance would open in the diagnosis of such conditions.