title: Metacarpal bone loss in patients with rheumatoid arthritis estimated by a new Digital X-ray Radiogrammetry method - initial results.
abstract: The Digital X-ray Radiogrammetry (DXR) method measures the cortical bone thickness in the shafts of the metacarpals and has demonstrated its relevance in the assessment of hand bone loss caused by rheumatoid arthritis (RA). The aim of this study was to validate a novel approach of the DXR method in comparison with the original version considering patients with RA.
  
  
  
  The study includes 49 patients with verified RA. The new version is an extension of the BoneXpert method commonly used in pediatrics which has these characteristics: (1) It introduces a new technique to analyze the images which automatically validates the results for most images, and (2) it defines the measurement region relative to the ends of the metacarpals. The BoneXpert method measures the Metacarpal Index (MCI) at the metacarpal bone (II to IV). Additionally, the MCI is quantified by the DXR X-posure System.
  
  
  
  The new version correctly analyzed all 49 images, and 45 were automatically validated. The standard deviation between the MCI results of the two versions was 2.9% of the mean MCI. The average Larsen score was 2.6 with a standard deviation of 1.3. The correlation of MCI to Larsen score was -0.81 in both versions, and there was no significant difference in their ability to detect erosions.
  
  
  
  The new DXR version (BoneXpert) validated 92% of the cases automatically, while the same good correlation to RA severity could be presented compared to the old version.
authors.affiliation: Department of Internal Medicine III, Jena University Hospital - Friedrich Schiller University Jena, Erlanger Allee 101, 07747, Jena, Germany. alexander.pfeil@med.uni-jena.de.
authors.forename: Alexander
authors.initials: A
authors.lastname: Pfeil
authors.affiliation: Visiana, Søllerødvej 57 C, DK-2840, Holte, Denmark.
authors.forename: Hans Henrik
authors.initials: HH
authors.lastname: Thodberg
authors.affiliation: Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Erlanger Allee 101, 07747, Jena, Germany.
authors.forename: Diane M
authors.initials: DM
authors.lastname: Renz
authors.affiliation: Department of Internal Medicine III, Jena University Hospital - Friedrich Schiller University Jena, Erlanger Allee 101, 07747, Jena, Germany.
authors.forename: Lisa
authors.initials: L
authors.lastname: Reinhardt
authors.affiliation: Department of Internal Medicine III, Jena University Hospital - Friedrich Schiller University Jena, Erlanger Allee 101, 07747, Jena, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Oelzner
authors.affiliation: Department of Internal Medicine III, Jena University Hospital - Friedrich Schiller University Jena, Erlanger Allee 101, 07747, Jena, Germany.
authors.forename: Gunter
authors.initials: G
authors.lastname: Wolf
authors.affiliation: Institute of Diagnostic and Interventional Radiology, SRH Wald-Klinikum Gera, Straße des Friedens 122, 07548, Gera, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Böttcher
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015519:Bone Density / Q000502:physiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D050279:Metacarpal Bones / Q000000981:diagnostic imaging*; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods / Q000592:standards*
keywords: Bone mineral density; BoneXpert; Cortical bone loss; Digital X-ray Radiogrammetry; Osteoporosis; Rheumatoid arthritis