Diagnostic Value of 18F-FDG-PET/CT in Patients with FUO

Abstract

<jats:p>Conventional diagnostic imaging is often ineffective in revealing the underlying cause in a considerable proportion of patients with fever of unknown origin (FUO). The aim of this study was to assess the diagnostic value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in patients with FUO. We retrospectively reviewed 18F-FDG-PET/CT scans performed on 50 consecutive adult patients referred to our department for further investigation of classic FUO. Final diagnosis was based on histopathological and microbiological findings, clinical criteria, or clinical follow-up. Final diagnosis was established in 39/50 (78%) of the patients. The cause of FUO was infection in 20/50 (40%), noninfectious inflammatory diseases in 11/50 (22%), and malignancy in 8/50 (16%) patients. Fever remained unexplained in 11/50 (22%) patients. 18F-FDG-PET/CT scan substantially contributed to the diagnosis in 70% of the patients, either by identifying the underlying cause of FUO or by directing to the most appropriate site for biopsy. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of 18F-FDG-PET/CT for active disease detection in patients with FUO were 94.7%, 50.0%, 84.0%, 85.7%, and 75.0%, respectively. In conclusion, whole-body 18F-FDG-PET/CT is a highly sensitive method for detection of the underlining cause of FUO or for correctly targeting suspicious lesions for further evaluation.</jats:p>

The Utility of 18FDG-PET/CT in Diagnosing Fever of Unknown Origin: The Experience of a Large Tertiary Medical Center

“…This variation can be explained, in part, by differences in the definitions of FUO, diagnostic algorithms and the place of 18FDG-PET/CT within the algorithms, technique and model of the 18FDG-PET/CT scanners, and by how usefulness of the 18FDG-PET/CT is defined [ 29 ]. Moreover, studies differed in whether they included immunocompromised patients and the extent to which immunosuppressive medications were used, widening the discrepancies [ 30 , 31 ].…”

“…The breakdown of how the test was classified by the judging clinicians and the statistical analysis of test properties were numerically comparable in those who underwent prior CT relative to the entire study cohort. Likewise, in a large study evaluating 18FDG-PET/CT in cases of FUO in which more than 70% of study participants had undergone prior chest and abdominal CT imaging, no correlation was detected between prior advanced diagnostic testing and whether 18FDG-PET/CT was found to be contributory [ 30 ].…”

The yield of F18 FDG PET-CT for the investigation of fever of unknown origin, compared with diagnostic CT

“…A previous retrospective study of 112 patients with the same characteristics, demonstrated a sensitivity and specificity of 72.2% and 57.5% respectively [5]. In another recent retrospective study of 50 patients with classical FUO, sensitivity reported for PET-CT was higher 94.7%, and specificity was much lower 50% [23].…”

Identify. Quantify. Predict. Why Immunologists Should Widely Use Molecular Imaging for Coronavirus Disease 2019

“…The increased availability of the technology over the past two and a half decades of its clinical implementation has also broadened its clinical applications, and imaging of inflammatory disease, e.g. in large vessel vasculitis, autoimmune encephalitis or fever without origin, are now established indications for FDG-PET/CT (29,(31)(32)(33). More recently, hybrid molecular imaging using FDG-PET/MRI has attracted attention for combining the superb imaging characteristics of both, MRI and PET in a simultaneous exam, defining a new imaging gold standard (34) with increasing sensitivity and specificity in soft tissue pathologies.…”