title: Prediction of femoral head collapse in osteonecrosis using 18F-fluoride positron emission tomography.
abstract: OBJECTIVE
  We investigated the usefulness of (18)F-fluoride PET as a predictor of femoral head collapse in patients with osteonecrosis (ON) before radiographic changes occur.
  
  
  METHODS
  Sixty-six hips of 42 patients diagnosed with ON of the femoral head were included in this study. We evaluated the relationship between the maximum standardized uptake value (SUV(max)) in (18)F-fluoride PET and the Ficat classification. We evaluated the relationship between SUV(max) and the presence of femoral head collapse on plain radiography at 12 months after (18)F-fluoride PET in 23 hips of 18 patients with Ficat classification stage 1 or 2. A receiver operating characteristic analysis was carried out to calculate the cut-off SUVmax for the prediction of femoral head collapse. We analyzed the relationship between SUV(max) and femoral head collapse on plain radiography in the 23 hips using a logistic regression model.
  
  
  RESULTS
  SUV(max) increased according to the progression of the Ficat classification stage. The mean SUV(max) was 12.3±5.9 in the collapse group and 4.9±1.3 in the noncollapse group (P<0.01). The cut-off SUV(max) of 6.45 (sensitivity: 0.80, specificity: 0.92) was used for the prediction of femoral head collapse. In the univariate analysis, SUV(max), type classification, and ring sign were related significantly to femoral head collapse.
  
  
  CONCLUSIONS
  We showed that the quantitative assessment of SUV(max) in (18)F-fluoride PET was useful to predict femoral head collapse in ON. (18)F-Fluoride PET might reflect accelerated bone metabolism because of microcollapse of the femoral head, which is undetectable on plain radiography.
authors.affiliation: Departments of aOrthopaedic Surgery bRadiology, Yokohama City University, Yokohama, Japan.
authors.forename: So
authors.initials: S
authors.lastname: Kubota
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Inaba
authors.forename: Naomi
authors.initials: N
authors.lastname: Kobayashi
authors.forename: Ukihide
authors.initials: U
authors.lastname: Tateishi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ike
authors.forename: Tomio
authors.initials: T
authors.lastname: Inoue
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Saito
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging*; D005459:Fluorides; D005462:Fluorine Radioisotopes; D006801:Humans; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D011379:Prognosis; D011859:Radiography; D055815:Young Adult
chemical_list: D005462:Fluorine Radioisotopes; D005459:Fluorides