Usefulness of 18F-FDG PET-CT in the Management of Febrile Neutropenia: A Retrospective Cohort from a Tertiary University Hospital and a Systematic Review.

Febrile neutropenia (FN) is a complication of hematologic malignancy therapy. An early diagnosis would allow optimization of antimicrobials. The 18F-FDG-PET-CT may be useful; however, its role is not well established. We analyzed retrospectively patients with hematological malignancies who underwent 18F-FDG-PET-CT as part of FN management in our university hospital and compared with conventional imaging. In addition, we performed a systematic review of the literature assessing the usefulness of 18F-FDG-PET-CT in FN. A total of 24 cases of FN underwent 18F-FDG-PET-CT. In addition, 92% had conventional CT. In 5/24 episodes (21%), the fever was of infectious etiology: two were bacterial, two were fungal, and one was parasitic. When compared with conventional imaging, 18F-FDG-PET-CT had an added value in 20 cases (83%): it diagnosed a new site of infection in 4 patients (17%), excluded infection in 16 (67%), and helped modify antimicrobials in 16 (67%). Antimicrobials could be discontinued in 10 (41.6%). We identified seven publications of low quality and one randomized trial. Our results support those of the literature. The available data suggest that 18F-FDG-PET-CT is useful in the management of FN, especially to diagnose fungal infections and rationalize antimicrobials. This review points out the low level of evidence and indicates the gaps in knowledge.

Are 18F-fluorodeoxyglucose positron emission tomography results reliable in patients with ascending aortic grafts? A prospective study in non-infected patients.

OBJECTIVES: Our goal was to define characteristic patterns of 18F-fluorodeoxyglucose in non-infected patients with ascending aortic prosthetic grafts during the first year after surgery. METHODS: 18F-fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT) was performed at 3, 6 and 12 months postoperatively in 26 uninfected patients. Clinical, analytical and microbiological (blood culture) assessments were performed to confirm the absence of infection. FDG uptake intensity [measured through maximum standardized uptake values (SUVmax) and the target-to-background ratio] and distribution patterns were obtained. Models of generalized estimating equations were used to assess the evolution of the SUVmax over time. The results were compared to those in our endocarditis-over-ascending-aortic-graft series database. The receiver operating characteristic curves of the control group and the 12-month group were assessed. RESULTS: All patients showed increased uptake in all areas. The uptake pattern was heterogeneous in 47.4%, 43.5% and 42.3% at 3, 6 and 12 months. The means and standard deviations of the SUVmax in the graft were 4.80 (±0.99), 4.28 (±0.88) and 4.14 (±0.87) at 3, 6 and 12 months after surgery. A comparison of all values obtained in the 6th and 12th months compared to those from the 3rd month revealed a slow decrease that may persist after the first year. The cut-off value of SUVmax of 4.24 had an overall sensitivity of 84.6% and specificity of 57.7% for patients seen at 12 months. CONCLUSIONS: Non-infected ascending aortic grafts showed no predominant uptake pattern; they also showed increased 18F-fluorodeoxyglucose activity that could persist beyond the first year. Caution is therefore recommended when interpreting PET/CT images obtained during the first year after surgery.

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.

Successful treatment of healthcare-associated Mycobacterium chimaera prosthetic infective endocarditis: the first Spanish case report.

BACKGROUND: Since 2011, several cases of health care-related disseminated Mycobacterium chimaera infection outbreaks have been reported subsequent to cardiac surgery. Diagnosis is difficult and the prognosis is extremely poor despite long-term antibiotic treatment and surgery. CASE SUMMARY: We report a Spanish case of M. chimaera infective endocarditis (IE) with disseminated infection. The patient was treated with long-term antibiotic therapy, valve replacement, and the novel use of interferon-gamma as adjuvant therapy. In addition, [18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) was used in combination with computed tomography (CT) to facilitate the diagnosis as well as to determine the duration of antibiotics and success of treatment. DISCUSSION: Diagnosing M. chimaera IE is difficult and requires a high index of clinical suspicion. Controlling the infection is even more difficult. Interferon-g used adjuvant to surgery and antibiotic therapy could be useful in achieving this goal. Given that the appropriate duration of antibiotics is unknown, FDG PET/CT could also be a valuable tool for determining when antibiotic therapy can be withdrawn.

Dynamic circulating tumor DNA quantificaton for the individualization of non-small-cell lung cancer patients treatment.

BACKGROUND: Liquid biopsy has evolved from being a promising line to becoming a validated approach for biomarker testing. However, its utility for individualization of therapy has been scarcely reported. In this study, we show how monitoring levels of EGFR mutation in plasma can be useful for the individualization of treatment. RESULTS: Longitudinal EGFR mutation levels in plasma always correlated with tumor response ascertained by RECIST criteria. Moreover, decreasing EGFR mutation levels were detected in all patients benefiting from locoregional radiotherapy, whereas the opposite occurred when a patient progressed soon after radiotherapy treatment. Similarly, increasing EGFR mutation levels anticipated disease progression after TKI dose reduction, discontinuation of treatment, or reduced bioavailability due to drug interactions. In addition, EGFR mutation levels were useful to monitor treatment outcome of new therapies and constituted a decisive factor when the clinical situation of the patient did not correlate with responses ascertained by radiologist. Finally, our results indicate that cancer associated body fluids (pleural, pericardial or cerebrospinal fluid) are certainly a suitable source for biomarker testing that can extend EGFR mutation detection to biofluids other than blood. MATERIALS AND METHODS: A total of 180 serial plasma samples from 18 non-small-cell lung cancer patients who carried an activating EGFR mutation were investigated by digital PCR. CONCLUSIONS: Monitoring levels of EGFR mutation in plasma allows resolving doubts that frequently arise in daily clinical practice and constitutes a major step towards achieving personalized medicine.