A fever of an Unknown Origin (FUO) is defined as a rectal temperature above 38.3 on at least two occasions with an illness duration of over three weeks and no apparent cause after one week of inpatient evaluation [1,2]. Following the failure to identify a source of fever in the initial workup for FUO, the recommended appropriate imaging modality is a fluorodeoxyglucose positron emission tomography with CT (FDG- PET/CT) with a diagnostic yield of 50 % [3]. Yet, a standard chest and abdominal CT has a long history of being the imaging test of choice in the "real world," with a diagnostic yield of approximately 30 % [1–5].
