title: Limitations of quantitative bone-mass measurements using assessments of first-order statistics of grey-level histograms in plain radiographs.
abstract: OBJECTIVE
  To evaluate the quality assurance of image-processing techniques in plain radiographs of skeletal structures.
  
  
  METHODS
  Twenty-two patients were studied, each with one osteolytic metastasis. Accuracy and precision of tube voltage and timer were confirmed. The mean value of grey-level histograms in plain radiographs (MVGLHs) was assessed. The deviation was monitored after five sets of sequential X-rays retaining the same settings for each radiograph.
  
  
  RESULTS
  Deviation was significantly higher in anatomical areas of thorax (21.2%) and abdomen (42.4%), while the consistency of MVGLH for weight-bearing bones was satisfactory with a maximum deviation of 2.9% (P<0.001, Kruskal-Wallis test).
  
  
  CONCLUSIONS
  Assessment of MVGLH in plain radiographs is a reliable method for the extremities and generally for regions without superimposed movable tissues.
authors.affiliation: Areteion University Hospital, Radiology Department, Athens, Greece. vkouloul@cc.ece.ntua.gr
authors.forename: V E
authors.initials: VE
authors.lastname: Kouloulias
authors.forename: G
authors.initials: G
authors.lastname: Matsopoulos
authors.forename: J R
authors.initials: JR
authors.lastname: Kouvaris
authors.forename: C
authors.initials: C
authors.lastname: Antypas
authors.forename: N C
authors.initials: NC
authors.lastname: Uzunoglu
authors.forename: M N
authors.initials: MN
authors.lastname: Varela
authors.forename: A
authors.initials: A
authors.lastname: Metafa
authors.forename: P
authors.initials: P
authors.lastname: Sandilos
authors.forename: L J
authors.initials: LJ
authors.lastname: Vlahos
mesh_terms: D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011785:Quality Assurance, Health Care; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000592:standards*; D018709:Statistics, Nonparametric