[18F] FDG PET/CT in patients with fever of unknown origin: a local experience

2-deoxy-2-[¹⁸F]fluoro-D-glucose positron emission tomography/computed tomography ([¹⁸F] FDG PET/CT) has become an established imaging tool in oncology and is now emerging in the field of infectious disease. The aim of this study is to assess the value of fluorine [¹⁸F] FDG PET/CT in the investigation of patients with fever of unknown origin (FUO).

[¹⁸F] FDG PET/CT scans and clinical data of 12 patients were reviewed. These patients met the revised definition criteria of FUO (febrile illness of greater than 3 weeks duration, temperature greater than 38.3°C and no diagnosis after at least 3 days of in-patient investigation or 2 weeks of outpatient investigation). A retrospective analysis of our local database was performed and evaluated for the diagnostic contribution of [¹⁸F] FDG PET/CT scans.

An infective cause of the FUO was found in four (33.3%) patients, a neoplasm in two (16.7%) patients, non-infectious inflammatory disease or autoimmune in one (8.3%) patient. A definitive causative agent could not be found in five (41.7%) patients despite extensive investigations.In all, five (41.6%) patients had a PET/CT scan that was abnormal and was deemed 'helpful' as part of the investigation that pointed to the final diagnosis. Two (16.7%) patients had abnormal scans, which were deemed 'not-helpful' for the final diagnosis.

[¹⁸F] FDG PET/CT can be helpful in some patients with FUO. This study adds value to the limited data published so far on this subject.