title: Diagnostic utility of fluorodeoxyglucose positron emission tomography/computed tomography in pyrexia of unknown origin.
abstract: OBJECTIVE
  The present study was undertaken to evaluate the diagnostic utility of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) in patients presenting as pyrexia of unknown origin (PUO).
  
  
  METHODS
  Forty-seven patients (31 males and 16 females; mean age of 42.7 ± 19.96 years) presenting as PUO to the Department of Medicine at the All India Institute of Medical Sciences, New Delhi over a period of 2 years underwent F-18 FDG PET/CT. PET ⁄ CT was considered supportive when its results correlated with the final definitive diagnosis. Final diagnosis was made on the basis of combined evaluation of history, clinical findings, investigations, and response to treatment.
  
  
  RESULTS
  Thirty-five PET/CT studies (74.5%) were positive. However, only 18 (38.3%) were supportive of the final diagnosis. In three patients (6.4%), PET/CT was considered diagnostic as none of the other investigations including contrast-enhanced computed tomography of chest and abdomen, and directed tissue sampling could lead to the final diagnosis. All these three patients were diagnosed as aortoarteritis.
  
  
  CONCLUSIONS
  Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography is an important emerging modality in the workup of PUO. It supported the final diagnosis in 38% of our patients and was diagnostic in 6.4% of patients. Thus, PET/CT should only be considered as second-line investigation for the diagnostic evaluation of PUO; especially in suspected noninfectious inflammatory disorders.
authors.affiliation: Department of Medicine, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Nidhi
authors.initials: N
authors.lastname: Singh
authors.affiliation: Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Department of Nuclear Medicine, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
authors.forename: Arun
authors.initials: A
authors.lastname: Malhotra
authors.affiliation: Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Ashu Seith
authors.initials: AS
authors.lastname: Bhalla
authors.affiliation: Department of Medicine, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Uma
authors.initials: U
authors.lastname: Kumar
authors.affiliation: Department of Medicine, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Rita
authors.initials: R
authors.lastname: Sood
keywords: Fever; fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography; pyrexia; pyrexia of unknown origin