title: Cancellous bone changes in the radius of patients with rheumatoid arthritis: a cross-sectional quantitative macroradiographic study.
abstract: OBJECTIVE
  Fractal signature analysis (FSA), a computerized method of textural analysis, permits the separate measurement of changes in vertical and horizontal trabeculae based on the fractal dimension over a range of trabecular widths (fractal signature). We determined whether the FSA of high-definition macroradiographs (x5 magnification) quantified radiographic changes at sites of osteopenia and erosion formation in the rheumatoid arthritis (RA) hand.
  
  
  METHODS
  Sixty-seven RA patients had macroradiographs of the left wrist and hand. The distal radius was scored and grouped from very mild (RA1) to moderate (RA4) disease. Macroradiographs were digitized and FSA of horizontal and vertical trabecular organization was performed in the radius at sites of periarticular osteopenia, erosion formation and at a mid-metaphyseal site. The RA groups were compared with 11 healthy non-arthritic subjects using ANOVA and Dunnett's tests.
  
  
  RESULTS
  Compared to the non-arthritic hands, FSA at the distal radius in groups RA1 to RA4 measured significantly lower (P<0.05) fractal signatures. The fractal signatures were lowest in RA4 involving small, medium to large sized vertical trabeculae at the periarticular osteopenic (0.18 to 0.84 mm, P<0.01) and mid-metaphyseal sites (0.12 to 0.60 and 0.84 to 1.02 mm, P </= 0.04), and small to medium sized vertical trabeculae at the periarticular erosion site (0.24 to 0.84 mm, P<0.01).
  
  
  CONCLUSIONS
  FSA quantified radiographic bone loss in the distal radius of RA patients with increasing radiographic severity in terms of lower fractal signatures compared with the non-arthritics. Disease-related bone loss was demonstrated by FSA to involve mainly vertical trabeculae at the periarticular osteopenic, periarticular erosion and the mid-metaphyseal sites indicating directionality of bone resorption in RA.
authors.affiliation: Department of Applied Clinical Anatomy Research Centre, School of Biomedical Sciences, King's College London, Hodgkin Building, Guy's Campus, London Bridge, London SE1 1UL, UK.
authors.forename: L
authors.initials: L
authors.lastname: Disini
authors.forename: M
authors.initials: M
authors.lastname: Foster
authors.forename: P J
authors.initials: PJ
authors.lastname: Milligan
authors.forename: J C
authors.initials: JC
authors.lastname: Buckland-Wright
mesh_terms: D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001851:Bone Diseases, Metabolic / Q000000981:diagnostic imaging / Q000503:physiopathology; D001842:Bone and Bones / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D005260:Female; D017709:Fractals; D006225:Hand / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D011859:Radiography; D011884:Radius / Q000000981:diagnostic imaging / Q000503:physiopathology; D014955:Wrist Joint / Q000000981:diagnostic imaging / Q000503:physiopathology