Abstract
Background: Fever and inflammatory syndrome of unknown origin pose diagnostic challenges, particularly in elderly patients with atypical presentations. (18)F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography ((18)F-FDG PET/CT) has proven useful in these cases, yet its role in geriatric populations remains underexplored. This study evaluates the impact of (18)F-FDG PET/CT on the management of these conditions in elderly patients. Methods: A retrospective study of patients aged ≥75 years who underwent (18)F-FDG PET/CT between 2013 and 2018 for unexplained fever or inflammatory syndrome was conducted. The primary outcome was the impact of (18)F-FDG PET/CT on treatment decisions, defined as any change in treatment within 6 months of the scan request. Therapeutic changes included the initiation of new treatments or discontinuation of existing ones, regardless of the diagnosis. Results: Ninety-three patients (mean age: 82.2 years) were included. (18)F-FDG PET/CT contributed to a definitive diagnosis in 30.8% of cases, with infections (19.8%), inflammatory diseases (19.8%), and malignancies (14.3%) being the most frequent diagnoses. Of the 61 patients who underwent further testing, 33 (39.3%) had targeted tests based on the (18)F-FDG PET/CT findings. Histology was obtained for 28 patients, with 18 targeted biopsies. Therapeutic modifications occurred in 38.8% of cases, with new treatments initiated in 33.3% and treatment discontinued in 10%. False positives occurred in 15.2% of cases. Conclusions:(18)F-FDG PET/CT is a valuable tool in managing elderly patients with unexplained fever or inflammatory syndrome, aiding diagnosis and therapeutic decisions. Its use should be considered in the elderly population but must be carefully weighed against the patient's frailty and the available treatment options.