title: Assessment of risk of femoral neck fracture with radiographic texture parameters: a retrospective study.
abstract: OBJECTIVE
  To investigate whether femoral neck fracture can be predicted retrospectively on the basis of clinical radiographs by using the combined analysis of bone geometry, textural analysis of trabecular bone, and bone mineral density (BMD).
  
  
  METHODS
  Formal ethics committee approval was obtained for the study, and all participants gave informed written consent. Pelvic radiographs and proximal femur BMD measurements were obtained in 53 women aged 79-82 years in 2006. By 2012, 10 of these patients had experienced a low-impact femoral neck fracture. A Laplacian-based semiautomatic custom algorithm was applied to the radiographs to calculate the texture parameters along the trabecular fibers in the lower neck area for all subjects. Intra- and interobserver reproducibility was calculated by using the root mean square average coefficient of variation to evaluate the robustness of the method.
  
  
  RESULTS
  The best predictors of hip fracture were entropy (P = .007; reproducibility coefficient of variation < 1%), the neck-shaft angle (NSA) (P = .017), and the BMD (P = .13). For prediction of fracture, the area under the receiver operating characteristic curve was 0.753 for entropy, 0.608 for femoral neck BMD, and 0.698 for NSA. The area increased to 0.816 when entropy and NSA were combined and to 0.902 when entropy, NSA, and BMD were combined.
  
  
  CONCLUSIONS
  Textural analysis of pelvic radiographs enables discrimination of patients at risk for femoral neck fracture, and our results show the potential of this conventional imaging method to yield better prediction than that achieved with dual-energy x-ray absorptiometry-based BMD. The combination of the entropy parameter with NSA and BMD can further enhance predictive accuracy.
authors.affiliation: From the Department of Medical Technology (J.T., J.H., P.P., M.M., R.K., S.S., T.J.) and Institute of Health Sciences (R.K.), University of Oulu, PO Box 5000, Oulu 90014, Finland; Department of Sports and Exercise Medicine, Oulu Deaconess Institute, Oulu, Finland (R.K.); Institute of Health Sciences (R.K.) and Department of Diagnostic Radiology (S.S., T.J.), Medical Research Center Oulu, Oulu University Hospital and University of Oulu (J.T., J.H., P.P., M.M., R.K., S.S., T.J.).
authors.forename: Jérôme
authors.initials: J
authors.lastname: Thevenot
authors.forename: Jukka
authors.initials: J
authors.lastname: Hirvasniemi
authors.forename: Pasi
authors.initials: P
authors.lastname: Pulkkinen
authors.forename: Mikko
authors.initials: M
authors.lastname: Määttä
authors.forename: Raija
authors.initials: R
authors.lastname: Korpelainen
authors.forename: Simo
authors.initials: S
authors.lastname: Saarakkala
authors.forename: Timo
authors.initials: T
authors.lastname: Jämsä
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D015519:Bone Density; D005260:Female; D005265:Femoral Neck Fractures / Q000000981:diagnostic imaging*; D006801:Humans; D018579:Patient Selection; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors