title: F-18 fluoride positron emission tomography/computed tomography in the diagnosis of avascular necrosis of the femoral head: Comparison with magnetic resonance imaging.
abstract: OBJECTIVE
  Femoral head avascular necrosis (FHAVN) is one of the increasingly common causes of musculoskeletal disability and poses a major diagnostic and therapeutic challenge. Although radiography, scintigraphy, computed tomography (CT), and magnetic resonance imaging (MRI) have been widely used in the diagnosis of FHAVN, positron emission tomography (PET) has recently been evaluated to assess vascularity of the femoral head. In this study, the authors compared F-18 fluoride PET/CT with MRI in the initial diagnosis of FHAVN.
  
  
  METHODS
  We prospectively studied 51 consecutive patients with a high clinical suspicion of FHAVN. All patients underwent MRI and F-18 fluoride PET/CT, the time interval between the two scans being 4-10 (mean 8) days. Two nuclear medicine physicians blinded to the MRI report read the PET/CT scans. Clinical assessment was also done. Final diagnoses were made by surgical pathology or clinical and radiologic follow-up.
  
  
  RESULTS
  A final diagnosis of avascular necrosis (AVN) was made in 40 patients. MRI was 96.5% sensitive, 100% specific, and 98.03% accurate while PET/CT was 100% sensitive, specific, and accurate in diagnosing FHAVN. The agreement between the two imaging modalities for the diagnosis of AVN was 96.07%.
  
  
  CONCLUSIONS
  F-18 fluoride PET/CT showed good agreement with MRI in the initial diagnosis of FHAVN and can be better than MRI in detecting early disease.
authors.affiliation: Department of Nuclear Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Shankaramurthy
authors.initials: S
authors.lastname: Gayana
authors.affiliation: Department of Nuclear Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Anish
authors.initials: A
authors.lastname: Bhattacharya
authors.affiliation: Department of Orthopedics, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Ramesh Kumar
authors.initials: RK
authors.lastname: Sen
authors.affiliation: Department of Radiodiagnosis, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Paramjeet
authors.initials: P
authors.lastname: Singh
authors.affiliation: Department of Radiodiagnosis, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Mahesh
authors.initials: M
authors.lastname: Prakash
authors.affiliation: Department of Nuclear Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Bhagwant Rai
authors.initials: BR
authors.lastname: Mittal
keywords: Avascular necrosis; F-18 fluoride; femoral head; magnetic resonance imaging; positron emission tomography/computed tomography