Clinical Utility of 18F-FDG PET/CT in Patients With Hypereosinophilia

PURPOSE: Hypereosinophilia (HE) is a rare disease with complex and diverse causes. Therapeutic strategies for HE differ because of its diverse causes, demanding advanced diagnostic tools for accurate assessment. This study evaluated the role of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) in determining the etiology of HE. MATERIALS AND METHODS: This retrospective single-center study consecutively included 78 patients with HE who underwent 18 F-FDG PET/CT examinations between 2011 and 2022. The diagnostic value of 18 F-FDG PET/CT in identifying the etiology of HE was assessed. Logistic regression analyses were conducted to determine the clinical and laboratory factors associated with 18 F-FDG PET/CT outcomes. RESULTS: Seventy-eight patients aged 44.58±17.01 years had different conditions: infectious diseases, n=9 [11.54%]; noninfectious inflammatory diseases, n=23 [29.49%]; solid tumors or hematological malignancies, n=16 [20.51%]; lymphocyte-variant HE, n=1 [1.28%]; and idiopathic HE or idiopathic hypereosinophilic syndrome, n=29 [37.18%]. 18 F-FDG PET/CT was used to identify the etiology in 48 patients (61.54%, true positive), whereas secondary causes were ruled out in 21 patients (26.92%), leading to a diagnosis of idiopathic HE. 18 F-FDG PET/CT achieved a diagnostic sensitivity of 92.31%, specificity of 80.77%, and accuracy of 88.46%. The presence of symptoms was positively correlated with true-positive PET/CT results (odds ratio: 2.940, 95% CI: 1.073-8.055), whereas immunoglobulin E level exhibited no association. CONCLUSIONS: 18 F-FDG PET/CT showed high sensitivity and accuracy in identifying the etiology of HE, making it a valuable tool for assessing elevated eosinophil counts.