The Diagnostic Role of FDG PET/CT in Patients with Fever of Unknown Origin

Objective: Fever of unknown origin (FUO) is a challenge for the physician and needs use of clinical, laboratory, and imaging studies and also invasive and/or non-invasive interventions to detect the etiology. The aim of present study was to assess the role of FDG PET/CT in determining the etiology in patients with FUO. Material and Methods: Twenty-four patients (median age 52, range 5-77 years, 6 female, 18 male) who were diagnosed with FUO were retrospectively analyzed in this study. Before the FDG PET/CT studies, none of them had a definitive reason for their diseases investigated by conventional radiological or scintigraphic methods, clinical and laboratory observations. Results: The positive result was achieved in 19 (79.2%) of 24 patients as findings of the FDG PET/CT. However, FDG PET/CT was useful for definitive diagnosis in 12 (63.2%) of 19 positive patients. Malignant diseases were determined to be the underlying cause of FUO in 5 (41.6%) of 12 patients. Noninfectious inflammatory causes were detected in 2 (16.7%) patients, infections were exhibited in 3 (25%) patients, and miscellaneous diseases demonstrated in 2 (16.7%) patients. In 7 patients the detected pathological uptakes on FDG PET/CT were not helpful for the definitive diagnosis. In remaining 5 patients who showed no pathological uptake in the FDG PET/CT, diagnosis could not be established by other methods, as well. The sensitivity, specificity, and positive and negative predictive values for the determination of FUO etiology were 92.3%, 45.4%, 63.1%, and 100% for FDG PET/CT. Conclusion: Our results demonstrate that FDG PET/CT seems to have considerable contribution to reveal the reason of undiagnosed patients with FUO investigated by conventional diagnostic methods, clinical and laboratory observations. (MIRT 2011; 20: 19-25

Role of contrast-enhanced F-18-FDG PET/CT imaging in the diagnosis and staging of renal tumors

WOS: 000451811700015PubMed: 30234688Purpose the objectives of this prospective study are to compare intravenous contrast-enhanced (CE) fluorine-18-fluorodeoxyglucose (F-18-FDG) PET/computed tomography (CE F-18-FDG PET/CT) with conventional methods (CT/MRI) and to evaluate the relationship of maximum standardized uptake value (SUVmax) with Fuhrman grade in patients with renal tumors. Patients and methods A total of 62 patients [35 males and 27 females; mean age 55.8 +/- 12.7 (range: 27-81) years] were enrolled in the study. CE F-18-FDG PET/CT scanning included whole-body (early) and abdominal imaging (late) 1 and 2 h after intravenous F-18-FDG administration, respectively. SUVmax was calculated for primary tumors. CE F-18-FDG PET/CT and CT/MRI findings were compared with respect to primary tumors and staging. Results the sensitivity of CE F-18-FDG PET/CT in primary tumor detection was 98%, which was very close to that of CT/MRI (100%). CE F-18-FDG PET/CT resulted in correct staging in 84% of the cases, compared with 68% of the cases with conventional methods (52 vs. 42 patients). SUVmax values of early PET for the primary tumors were significantly correlated with the Fuhrman grades (P<0.001). CE F-18-FDG PET/CT enabled the detection of synchronous tumors in four patients, one of which was incorrectly diagnosed as having metastasis by CT. Distant metastases were detected in 16 patients with CE F-18-FDG PET/CT and in 13 patients with routine conventional methods. Conclusion CE F-18-FDG PET/CT showed similar results compared with CT/MRI in the detection of primary tumors, but it was superior to conventional methods in the detection of metastasis and staging. Given the highly significant correlation between SUVmax values and the Fuhrman grading, CE F-18-FDG PET/CT may play a significant role in the evaluation of patient prognosis