The diagnostic role of (18)F fluorodeoxyglucose positron emission tomography in patients with fever of unknown origin.

Abstract

Identification of aetiology for fever of unknown origin (FUO) is challenging, due to the high rates of undiagnosed cases. The current diagnostic approach includes initially first-line procedures such as general examination and various laboratory tests and basic imaging techniques followed by second-line tests such as more advanced imaging techniques including (18)F fluorodeoxyglucose positron emission tomography (FDG PET) and tissue biopsies. If no diagnosis is obtained, more invasive measures may be in order such as liver biopsy and exploratory laparotomy. This review article is based on the relative published material found on MEDLINE and PubMed up to August 2014. We looked for the terms 'fever of unknown origin, FDG PET' in combination with 'cancer, infection and autoimmune disease'. Several clinical studies have investigated the utility of the FDG PET during the diagnostic approach of FUO. Recent evidence suggests that FDG PET has the advantage of total body imaging and may depict all common causes of FUO such as infections, noninfectious inflammatory causes and tumours because they all exhibit glucose hypermetabolism. Depiction of an abnormal lesion on FDG PET could guide clinicians to the next diagnostic procedure (another imaging method, culture, biopsy or surgery) to establish the diagnosis. Emerging evidence suggests that FDG PET, when available, may provide critical diagnostic information early during evaluation of FUO.