title: Short-time in vitro and in vivo precision of direct digital X-ray radiogrammetry.
abstract: Digital X-ray radiogrammetry (DXR) calculates peripheral bone mineral density (BMD) from hand radiographs. The aim of this study was to examine in vitro and in vivo precision for the new direct digital version of DXR, a development of the conventional DXR. The in vitro precision for direct DXR was tested on 4 different X-ray equipment, based on 31 radiographs of the same phantom. The in vivo precision was based on duplicate hand radiographs from both hands in 39 individuals. For the 4 X-ray equipment, in vitro precision ranged from 0.14% to 0.30%, expressed as coefficient of variations (CV%) and from 0.0012 to 0.0028 g/cm2, expressed as smallest detectable difference (SDD). The precision was correlated to the resolution of the radiographic equipment (r=0.95, p=0.05). The corresponding values for the in vivo precision for mean values of both hands were: CV%=0.46%; SDD=0.0046 g/cm2, and least significant change (LSC%)=1.28%. The DXR-BMD for 1 of the X-ray equipment differed 1.1% from the overall mean. The precision for direct DXR was highly satisfactory both in vitro and in vivo. DXR-BMD values may differ between the radiographic equipment, and follow-up measurements should be performed with the same X-ray equipment.
authors.affiliation: Department of Rheumatology, St. Olav's Hospital, and Norwegian University of Science and Technology, Department of Neuroscience, Trondheim, Norway. mari.hoff@ntnu.no
authors.forename: Mari
authors.initials: M
authors.lastname: Hoff
authors.forename: Alvilde
authors.initials: A
authors.lastname: Dhainaut
authors.forename: Tore K
authors.initials: TK
authors.lastname: Kvien
authors.forename: Kristina
authors.initials: K
authors.lastname: Forslind
authors.forename: Johan
authors.initials: J
authors.lastname: Kälvesten
authors.forename: Glenn
authors.initials: G
authors.lastname: Haugeberg
mesh_terms: D015519:Bone Density; D005385:Fingers / Q000000981:diagnostic imaging*; D006225:Hand / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D050279:Metacarpal Bones / Q000000981:diagnostic imaging* / Q000502:physiology* / Q000503:physiopathology; D010024:Osteoporosis / Q000175:diagnosis*; D011856:Radiographic Image Enhancement