The diagnostic utility of computed tomography scans performed for febrile neutropenia in a single centre.

BACKGROUND: Computed tomography (CT) imaging has become a first line investigation for most cases of febrile neutropenia (FN) which can be the only sign of infection in oncology patients undergoing active chemotherapy and bone marrow transplants. The utility of routine non-targeted imaging remains unclear. OBJECTIVE: To assess and compare the diagnostic rate between targeted, non-targeted and pan-scan CT in identifying an acute source of infection in adult oncology patients with FN. MATERIALS AND METHODS: A retrospective observational study was conducted between February 2019 and March 2023 on 417 consecutive CT examinations for the clinical indication of source identification in FN. Scans were noted for the anatomical regions that were imaged and reports were classified as positive, negative or equivocal for infection. Pre-existing pathology was also noted. Results were tabulated and statistical analyses for comparison between groups of scans was performed using chi-square test. RESULTS: All targeted regional scans had statistically significant difference in positive rate compared to non-targeted scans of the respective region; chest (Χ²(1)=18.11, P<.001); sinus (Χ²(1)=15.36, P<.001); abdomen and pelvis (Χ²(1)=5.95, P=.01). Pneumonia (41.3 %) was much more likely to be the diagnosis compared to sinusitis (16.2 %) in concomitant CT chest to sinus examinations (Χ²(1)=45.3, P<.001). Pan-scans had a higher incidence of positive diagnosis compared to all-targeted scans (Χ²(1)=4.91, P=.03) but when compared to higher yield targeted scans (abdomen and chest), there was no statistical difference (Χ²(1)=2.43, P=.12). 20/54 patients had pan-scans despite having localising symptoms. CONCLUSION: Imaging guided by presenting signs and symptoms can help to reduce unnecessary imaging and promote more judicious use of non-targeted and pan-scan CT in current practices.

Chest CT Has Higher Yield for Infection than CT Sinus in Febrile Neutropenic Patients.

OBJECTIVE: Chest and sinus CT imaging among cancer patients undergoing chemotherapy and bone marrow transplant in the setting of neutropenic fever is not uncommon, yet the utility of routine imaging surveillance remains unclear. We aim to compare the rates of acute infection detected on CT chest and CT sinus exams performed in this clinical setting. METHODS: Reports of 1059 consecutive CT chest and sinus examinations for the clinical indication of neutropenic fever on 262 patients performed between January through June 2017 were retrospectively reviewed. Infection as reported was characterized as acute or worsening, improving, stable, indeterminate or negative. Results were tabulated and Pearson's chi-square test was used for comparison analysis. RESULTS: Absence of infection on CT sinus was significantly higher than CT chest (86.1% vs. 58.5%; P<0.001). Conversely, CT chest had significantly higher incidence of acute or worsening infection than CT sinus (28.7% vs. 11.6%; P<0.001). CT chest also showed significantly higher incidence of improving infection compared to CT sinus (6.2% vs. 1.1%; P<0.001). There was no significant difference between incidence of stable infection on CT chest and CT sinus (1.1% vs. 0.2%; P=0.059). Infection was indeterminate in 5.5% of CT chest vs. 1% on CT sinus (P<0.001). CONCLUSIONS: CT chest showed significantly higher diagnostic yield for acute infection than CT sinus, suggesting that sinusitis is less likely to be the source of fever than chest infections in febrile neutropenic patients. The majority of CT studies showed absence of infection, raising the question of the overall utility of routine surveillance CT imaging among this subset of patients.

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.

Procalcitonin and C-Reactive Protein As Markers of Bacteremia in Patients With Febrile Neutropenia Who Receive Chemotherapy for Acute Leukemia: A Prospective Study From Nepal.

PURPOSE: The purpose of this study was to evaluate the clinical significance of the biomarkers procalcitonin (PCT) and C-reactive protein (CRP) in patients with febrile neutropenia (FN) undergoing chemotherapy for acute leukemia. METHODS: We conducted a prospective, observational study in patients who developed FN while undergoing chemotherapy for acute leukemia. PCT and CRP were obtained in patients who presented with FN. Blood cultures also were obtained. The primary goals were to evaluate the ability of PCT and CRP to predict bacteremia in patients with FN. The secondary goals were to assess the prognostic role of PCT and CRP and to assess the microbiologic profile and culture sensitivity patterns in the study population. RESULTS: A total of 124 episodes of FN that involved 67 patients with acute leukemia occurred in the study. PCT was superior to CRP in the prediction of bacteremia. The median PCT level in the bacteremia group was 3.25 ng/mL compared with 0.51 ng/mL in the group without bacteremia (P < .01). The median values of CRP in the bacteremia and without-bacteremia groups were 119.3 mg/L and 94.5 mg/L, respectively (P = .07). There were no differences in median PCT and CRP in patients who died and those who improved. Of the 42 positive cultures, Gram-negative bacteremia was common (86%), and Escherichia coli was the most frequent organism isolated. Carbapenem resistance was seen in 39% of positive cultures. CONCLUSION: PCT is an effective biomarker to predict bacteremia in patients with FN undergoing chemotherapy for acute leukemia.

Low-dose computed tomography in assessment of pulmonary abnormalities in children with febrile neutropenia suffering from malignant diseases.

BACKGROUND: Management of febrile neutropenia in pediatric patients is challenging. Chest X-ray and CT scan help to identify infective foci; however, exposure to radiation is a risk factor for development of secondary cancer. For this reason, attention is paid to reducing radiation exposure. OBJECTIVES: The aim of the study was to define the role of LDCT examination in the early detection of pulmonary lesions in children during oncology or autoimmune treatment complicated by neutropenia-related fever. Additionally, we focused on the possibility to optimize image quality in low-dose protocols. MATERIAL AND METHODS: The study included 138 pediatric patients (mean age 8.08 years) with fever of 38.2°C or higher with an absolute neutrophil count of 10 mm with or without surrounding GGO or cavitations was sensitive at 77% and specific at 65% for fungal infection insert after neutrophil count: < 500/pL who underwent chest X-ray and LDCT in the maximal interval of 24 h. CT findings were compared with initial and final diagnosis as well as with clinical information. RESULTS: LDCT detected pulmonary abnormalities in 116 patients (84.06%) showing ground-glass opacities (GGO) (n = 79), nodules (n = 60) and air-space consolidations (n = 58). Radiologists correctly diagnosed infective lesions in 94 out of 116 patients (81.03%). The presence of random or pleural-based nodules. Diagnosis of pyogenic infection based on the presence of air-space consolidation, pleural effusion, GGO or centrilobular nodules showed a sensitivity of 78% and specificity of 67%, whereas patchy or diffuse GGO, interstitial thickening and/or air-space consolidation showed a high sensitivity of 81% and specificity of 68% for Pneumocystis jirovecii pneumonia. CONCLUSIONS: LDCT is an excellent modality in the diagnostic algorithm in patients with febrile neutropenia. It allows early detection and detailed characterization of pulmonary abnormalities. Using contrast, unenhanced CT examinations can further reduce radiation dose and diminish the number of complications without a negative influence on the diagnostic process.

Use of computed tomography abdomen and pelvis for investigation of febrile neutropenia in adult haematology patients.

We retrospectively evaluated the use of computed tomography abdomen and pelvis (CTAP) in febrile neutropenic autologous stem cell transplant (ASCT) and acute myeloid leukaemia (AML) patients. CTAP was more common in ASCT patients (59%) compared with AML (31%; P < 0.001). Although abnormal findings were reported in 51%, only 10% resulted in therapy change (addition of anaerobic antibiotic/bowel rest), which would have otherwise been instituted based on clinical grounds. CTAP in these patients rarely provide useful information unsuspected clinically.

¹8F-FDG-PET/CT Imaging in Patients with Febrile Neutropenia and Haematological Malignancies.

The aim of the present study was to assess the prevalence of hyper-metabolic infection sites revealed by fluorine-18 ((18)F) fluorodeoxyglucose (FDG) positron-emission tomography (PET) combined with computed tomography (CT) in patients with febrile neutropenia (FN). Forty-eight consecutive patients with haematological malignancies and persistent FN (temperature ≥ 38°C and neutrophil count <500 cells/µl for more than two days) as a consequence of intensive chemotherapy were prospectively included. Pathological FDG uptakes identified 31 foci of infections located in the lungs (n=15, 48.4 %), colon (n=4, 12.9%), pancreas (n=2, 6.5%), skin (n=3, 9.7%), ear-nose-throat area (n=5, 16.1%), central venous catheter tract (n=1, 3.2%) and gallbladder (n=1, 3.2%). These pathological FDG uptakes were observed in half of the 48 patients (n=24). Among the 38 patients with a clinical diagnosis of infection, 23 showed a pathological FDG uptake, resulting in a FDG-PET/CT sensitivity of 61% (95% CI, 43-76%). Our study confirmed the ability of FDG-PET/CT to diagnose infections in patients with persistent FN.

The utility of routine chest radiography in the initial evaluation of adult patients with febrile neutropenia patients undergoing HSCT.

BACKGROUND: The routine use of chest radiographs (CXRs) in the initial evaluation of asymptomatic patients with febrile neutropenia undergoing hematopoietic stem cell transplant (HSCT) is controversial. OBJECTIVE: The goal of this study was to document the incidence of pneumonia demonstrated on CXR during an initial febrile neutropenic episode in adult patients undergoing HSCT. MATERIALS AND METHODS: Clinical records of 1083 adult patients undergoing autologous (n=766), allogeneic (n=269), or umbilical cord blood HSCT (n=48) between October 1, 2009, and December 31, 2012, were retrospectively reviewed. CXRs obtained at the initial febrile neutropenic episode were evaluated for radiologic features of pneumonia. The presence of clinical symptoms, length of stay (LOS), and readmission rates were assessed. RESULTS: A total of 817 (75%) febrile neutropenic episodes were noted. Of the patients with neutropenic fevers, 455 (55%) had CXRs. Of the 76 patients with respiratory symptoms at the time of CXR, 24 (31.6%) had findings suggestive of pneumonia. None of the 379 CXRs performed in the absence of symptoms revealed an infectious process (P=.0001). Moreover, the mean LOS was 23.8 days for patients receiving a CXR compared with 22.2 days (P=.04) in patients without a CXR. Additionally, in patients who had CXRs, 15.7% were readmitted within 30 days compared with 7.4% in those without CXRs (P=.0004). CONCLUSIONS: Indiscriminate routine CXR at the time of first neutropenic fever in asymptomatic adults undergoing HSCT is unlikely to reveal an infectious process or change clinical practice, and may be associated with increased LOS and readmission rates.

The use of FDG-PET/CT in patients with febrile neutropenia.

Fever is a frequent complication of neutropenia induced by the treatment of various neoplasms. This is referred to as febrile neutropenia, which is considered to be a sign of a potentially life-threatening infectious complication until proven otherwise. However, most infectious foci do not have localizing signs and symptoms owing to the lack of inflammatory infiltrates during neutropenia. At the same time, recent studies also showed that febrile neutropenia is not a specific indicator for infection. An increase in C-reactive protein and fever may initially be caused by inflammation of the digestive tract mucosa due to cytotoxic treatment of hematologic malignancies. Infectious foci can be found in various organ systems, such as the respiratory tract including invasive fungal disease, septic thrombophlebitis in those patients with central venous catheters, metastatic infection including soft tissue abscesses, and the digestive tract, for example, colitis and esophagitis probably associated with mucosal barrier injury. A growing number of studies focus on the use of FDG-PET/CT to detect infection in patients with febrile neutropenia. Studies show that FDG uptake in inflammatory foci seems not to be hampered by the lack of circulating neutrophils. At the same time, the very high negative predictive value of FDG-PET/CT excluding localized infectious foci might facilitate guidance of antimicrobial treatment. However, larger prospective studies are needed before FDG-PET/CT would be embedded in diagnostic guidelines in patients with febrile neutropenia.