THE DIAGNOSTIC ROLE OF 18F-FDG-PET/CT IN PATIENTS WITH CONSTITUTIONAL SYMPTOMS

Objective: The contribution of 18F-FDG-PET/CT to diagnosis and its role in differential diagnosis were investigated in patients examined for constitutional symptoms.Materials and Methods: The 18F-FDG-PET/CT scan results and clinical data were analyzed retrospectively in 144 patients with constitutional symptoms examined between January 2017 and December 2019 in our outpatient and inpatient clinics in Istan-bul University Istanbul Faculty of Medicine Internal Medicine De-partment. The FDG uptake other than physiological FDG uptake was considered as PET-positive. Clinical, laboratory data, and 18F-FDG-PET/CT scan results were evaluated retrospectively from records.Results: The 144 patients comprised 85 (59.0%) men and 59 (41.0%) women with a mean age of 58.0 +/- 17.2 years. The mean duration of symptoms was 4.01 +/- 4.46 months. A definitive diag-nosis was established in 95.1% (n=137) of the patients based on physical examination, imaging methods, laboratory tests, and other diagnostic tests. In comparison, no definitive diagnosis was established in the remaining 4.9% (n=7) of the patients. 18F-FDG-PET/CT contributed to diagnosis in 86.8% (n=119) of patients. The patients were classified into four categories based on their diagnoses: (i) malignancies (n=79; 57.7%), (ii) rheumatic diseases (n=22; 16.1%), (iii) infectious diseases (n=19; 13.9%), and (iv) oth-er diseases (n=17; 12.4%). The sensitivity, specificity, and positive and negative predictive values of 18F-FDG-PET/CT in the diag-nosis of constitutional symptoms were 97.5%, 31.8%, 88.8%, and 70%, respectively.Conclusion: We found that 18F-FDG-PET/CT is a valuable diag-nostic tool in diagnosing patients with constitutional symptoms and provides high sensitivity and positive predictive value.