title: Correlation between baseline femoral neck marrow status and the development of femoral head osteonecrosis in corticosteroid-treated patients: a longitudinal study by MR imaging.
abstract: OBJECTIVE
  To test the hypothesis that the development of corticosteroid (CS)-associated femoral head osteonecrosis (ON) is influenced by baseline femoral neck marrow status.
  
  
  METHODS
  The population consisted of 20 untreated patients with a newly diagnosed rheumatic disease in whom a standardized CS regimen was planned. Before CS treatment, baseline femoral neck marrow status was determined by magnetic resonance (MR) imaging on T1-weighted images (proportion of surface area of femoral neck and intertrochanteric area occupied by fatty marrow; index of marrow conversion [IMC]) and on a quantitative MR sequence (bulk T1 values of femoral head and neck). The presence of ON was assessed by coronal T1-weighted MR images of the hips at 6 and 12 months.
  
  
  RESULTS
  None of the patients suffered from ON at baseline. Four patients (20%) developed bilateral femoral head ON at 6 months. The mean percentage of fat marrow in the femoral neck before treatment was significantly higher in ON-positive than in ON-negative patients (p=0.0025). The mean baseline femoral neck IMC value, which parallels the degree of red to yellow marrow conversion, was higher in ON-positive than in ON-negative patients (p=0.089). The mean baseline bulk T1 value of the femoral neck (but not of the femoral head), which inversely correlates with the amount of fat marrow, was significantly shorter in ON-positive than in ON-negative patients (p=0.0298).
  
  
  CONCLUSIONS
  The development of CS-associated femoral head ON is correlated with a high fat content in the proximal femur before CS therapy.
authors.affiliation: Radiology Department, Université Catholique de Louvain, Cliniques Universitaires Saint-Luc, Avenue Hippocrate 10, 1200 Brussels, Belgium. vandeberg@rdgn.ucl.ac.be
authors.forename: Bruno C
authors.initials: BC
authors.lastname: Vande Berg
authors.forename: Raphaël
authors.initials: R
authors.lastname: Gilon
authors.forename: Jacques
authors.initials: J
authors.lastname: Malghem
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lecouvet
authors.forename: Geneviève
authors.initials: G
authors.lastname: Depresseux
authors.forename: Frédéric A
authors.initials: FA
authors.lastname: Houssiau
mesh_terms: D000273:Adipose Tissue / Q000473:pathology; D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000009:adverse effects* / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D001853:Bone Marrow / Q000187:drug effects / Q000473:pathology*; D005260:Female; D005271:Femur Head Necrosis / Q000139:chemically induced* / Q000175:diagnosis*; D005500:Follow-Up Studies; D006621:Hip Joint / Q000187:drug effects / Q000473:pathology*; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012737:Sex Factors; D013997:Time Factors
chemical_list: D000305:Adrenal Cortex Hormones