title: Heterogeneity of bone microstructure in the femoral head in patients with osteoporosis: an ex vivo HR-pQCT study.
abstract: BACKGROUND
  Trabecular bone in the femoral head has a complicated and heterogeneous structure with few studies having analyzed heterogeneity in this structure quantitatively. We analyze trabecular bone microstructure in the femoral head with osteoporosis (OP) using high resolution peripheral quantitative CT (HR-pQCT) to investigate its regional characteristics.
  
  
  METHODS
  Fifteen femoral heads extracted from female OP patients with femoral neck fracture (85 ± 7, 67-94 years) were scanned by HR-pQCT at 41 μm voxel size. The femoral head was segmented into 15 regions (3 longitudinal regions: superior, center, and inferior, and 5 axial subregions: center, medial, lateral, anterior, posterior). Of these 15 regions, five were excluded due to overlap with the fracture site, leaving a total of 10 regions of cancellous bone microstructures to be quantitatively assessed using the following parameters: bone volume fraction, trabecular thickness, number, separation, connectivity density, structure model index, and degree and orientation of anisotropy. These parameters were compared among each region.
  
  
  RESULTS
  Trabecular bone at the center, superior, and supero-posterior regions of the femoral head had higher bone volume, trabecular number, thickness, narrower bone marrow spaces, higher connectivity and anisotropy, and more plate-like structure. This plate-like structure ran supero-inferiorly and antero-posteriorly at the superior and center regions. Bone volume at the anterior, posterior, and medial regions was almost half of the central and superior regions.
  
  
  CONCLUSIONS
  Significant heterogeneity of the trabecular bone microstructure in the OP femoral head was showed quantitatively in this study. These data offer new insight into bone microstructural anatomy and may prove to provide useful information on clinical medicine such as hip surgeries.
authors.affiliation: Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA. kohchiba@estate.ocn.ne.jp
authors.forename: Ko
authors.initials: K
authors.lastname: Chiba
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Burghardt
authors.forename: Makoto
authors.initials: M
authors.lastname: Osaki
authors.forename: Sharmila
authors.initials: S
authors.lastname: Majumdar
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016880:Anisotropy; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D009929:Organ Size; D010024:Osteoporosis / Q000000981:diagnostic imaging* / Q000473:pathology*; D014057:Tomography, X-Ray Computed
keywords: Bone microstructure; Femoral head; Femoral neck fracture; HR-pQCT; Osteoporosis