title: Proton MR spectroscopy of the femoral head--evaluation of patients at risk for avascular necrosis.
abstract: OBJECTIVE
  To detect alteration of the fatty component by measuring the in vivo lipid and water content of normal-looking femoral heads of patients with and without risk for avascular necrosis (AVN) by using proton MR spectroscopy (MRS).
  
  
  METHODS
  Marrow composition was measured by proton MRS (TR/TE = 5000/20 msec) in a sample volume placed in the epiphysis of the intact femoral heads of patients with unilateral osteonecrosis of the hip (group 1, N = 61, then excluding the post-traumatic or steroid user, final N = 45) and age-matched controls (group 2, N = 49). Three response variables were derived from MRS: the lipid linewidth (LW), water LW, and lipid/water ratio.
  
  
  RESULTS
  Of the three variables, the lipid and water LWs differed significantly between groups (P < 0.001 and P = 0.05, respectively; t-test). The lipid/water ratio had borderline significance (P = 0.06). The three variables differed significantly between groups when multivariate regression (P < 0.0001) was analyzed; and age and sex had no significant effect on the three dependent variables.
  
  
  CONCLUSIONS
  Proton MRS can depict alteration in the lipid and water composition of normal-looking femoral heads with and without AVN on the contralateral hip. Proton MRS may be a potential tool for investigating of the femoral head component in vivo and predicting the risk for development of AVN.
authors.affiliation: Department of Orthopedic Surgery, National Taiwan University Hospital, National Taiwan University, School of Medicine, Taipei, Taiwan.
authors.forename: Chun-han
authors.initials: CH
authors.lastname: Hou
authors.forename: Tiffany Ting-Fang
authors.initials: TT
authors.lastname: Shih
authors.forename: Chieh-Yu
authors.initials: CY
authors.lastname: Liu
authors.forename: Ying-Ding
authors.initials: YD
authors.lastname: Li
authors.forename: Tony
authors.initials: T
authors.lastname: Enright
mesh_terms: D000328:Adult; D001834:Body Water / Q000737:chemistry; D001853:Bone Marrow / Q000737:chemistry; D016022:Case-Control Studies; D005260:Female; D005271:Femur Head Necrosis / Q000175:diagnosis*; D006801:Humans; D008055:Lipids / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011522:Protons; D012044:Regression Analysis; D018570:Risk Assessment
chemical_list: D008055:Lipids; D011522:Protons