title: Cortical bone water changes in ovariectomized rats during the early postoperative period: Objective evaluation using sweep imaging with Fourier transform.
abstract: OBJECTIVE
  To evaluate the cortical bone signal-to-noise ratio (SNR) in ovariectomized (OVX) rats during the early postoperative period as a method to measure bone quality using the sweep imaging with Fourier transform (SWIFT) technique.
  
  
  METHODS
  Twelve-week-old female Sprague-Dawley rats (n = 64) were divided into sham and OVX groups. Preoperative tetracycline was immediately administered subcutaneously to distinguish new cortical bone area, and tibial samples were collected at 2, 4, 8, and 12 weeks postoperatively. Magnetic resonance imaging (MRI) was performed using proton density-weighted imaging (PDWI) and SWIFT to obtain cross-sectional images of the tibial diaphysis. The cortical bone SNR was calculated. Bone histomorphometry was performed.
  
  
  RESULTS
  Histomorphometry findings showed that the new bone area was significantly greater at 8 and 12 weeks postoperatively in the OVX group (P < 0.05) while the porosity area decreased gradually in both groups (P < 0.001). The difference of SNR receiving PDWI did not reach statistical significance (P = 0.057). The SWIFT technique showed that the SNR was significantly higher at 8 and 12 weeks postoperatively in the OVX group (P < 0.05) and was correlated with the new bone area (R(2) = 0.430).
  
  
  CONCLUSIONS
  The SWIFT findings suggest that the SWIFT technique may depict early changes in cortical bone quality.
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Sukenari
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Horii
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Ikoma
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Kido
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Hayashi
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Hara
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Yamasaki
authors.affiliation: Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Matsuda
authors.affiliation: Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Kawata
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kubo
mesh_terms: D000818:Animals; D001834:Body Water / Q000378:metabolism*; D005260:Female; D005583:Fourier Analysis; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010052:Ovariectomy; D011184:Postoperative Period; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013977:Tibia / Q000033:anatomy & histology* / Q000378:metabolism*
keywords: bone water; cortical bone; osteoporosis; ovariectomy; sweep imaging with Fourier transform