title: Bone homogeneity factor: an advanced tool for the assessment of osteoporotic bone structure in high-resolution magnetic resonance images.
abstract: OBJECTIVE
  Osteoporosis is characterized by low bone mass and inferior structural competence. In this study we introduce the bone homogeneity factor (BHF) as a quantitative measurement of bone structure, which could be equally important as bone mineral density.
  
  
  METHODS
  BHF represents an advanced texture analysis tool based on the spatial autocorrelation function calculated in 9 different directions. These calculations were performed on high-resolution magnetic resonance images of the calcaneus at 3.0 T and compared with dual-energy x-ray absorptiometry measurements of the femoral neck.
  
  
  RESULTS
  The quality and resolution of the high-resolution magnetic resonance images is sufficient for reliably calculating BHF. The mean BHF of the control group (n = 5, mean BHF = 525,0) with normal bone is significantly (P = 0.009, Mann-Whitney U test) higher than in the osteoporotic group (n = 7, mean BHF = 137,8). The BHF correlates with the DXA measurements of the femoral neck (correlation coefficient = 0.75).
  
  
  CONCLUSIONS
  By calculating the BHF, it was possible to distinguish between osteoporotic and nonosteoporotic bone structure. Hence, BHF could be a possible candidate for noninvasive assessment of osteoporotic bone structure giving additional information to routinely used bone mineral densitometry.
authors.affiliation: Department of Radiodiagnostics, University of Vienna, Medical School, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
authors.forename: Herbert
authors.initials: H
authors.lastname: Langenberger
authors.forename: Yu
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Christian
authors.initials: C
authors.lastname: Windischberger
authors.forename: Stephan
authors.initials: S
authors.lastname: Grampp
authors.forename: Andreas
authors.initials: A
authors.lastname: Berg
authors.forename: Katrin
authors.initials: K
authors.lastname: Ferlitsch
authors.forename: Ewald
authors.initials: E
authors.lastname: Moser
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D015519:Bone Density; D002111:Calcaneus / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D005272:Femur Neck; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D010024:Osteoporosis / Q000473:pathology*; D018709:Statistics, Nonparametric