Role of ¹⁸F-fluoro-D-glucose positron emission tomography/computed tomography in evaluation of patients with pyrexia of unknown origin

2-deoxy-2- (¹⁸F) fluoro-D-glucose positron emission tomography/computed tomography (¹⁸F- FDG PET/CT) has now become an established imaging tool in oncology. It is now emerging in the field of infectious diseases. The objective of this study was to assess the value of ¹⁸F-FDG PET/CT in investigating patients with pyrexia of unknown origin (PUO). After proper patient preparation and informed consent, a total of 36 referred patients (24 men, 12 women, with age range 21-63 years) underwent ¹⁸F-FDG- PET/CT for evaluation of pyrexia of unknown origin. All examinations were performed using dedicated LSO PET-CT scanner in 3-D mode, 60 min after i.v. injection of 370 MBq of ¹⁸F-FDG. No IV contrast was given. Reconstruction of the acquired data was performed so as to obtain fused PET-CT images in transaxial, coronal and sagittal views. Results: Twenty three out of 36 patients showed foci of increased FDG uptake in the whole body image thus helping in diagnosis and localising the active focus of disease. Remaining 13 patients did not show any area of abnormal FDG uptake. The sensitivity of ¹⁸F-FDG PET/CT for identifying the cause of PUO was 63.88%. ¹⁸F-FDG PET/CT in addition to contribution towards the diagnosis also helped in localization of disease. Our results suggest that ¹⁸F-FDG PET/CT may be used as an initial non-invasive diagnostic modality for assessment of patients with pyrexia of unknown origin. (author)