Short-Time In Vitro and In Vivo Precision of Direct Digital X-ray Radiogrammetry

Hoff, Mari; Dhainaut, Alvilde; Kvien, Tore K.; Forslind, Kristina; Kälvesten, Johan; Haugeberg, Glenn

doi:10.1016/j.jocd.2008.10.005

« Previous Next »Journal of Clinical Densitometry
Volume 12, Issue 1 , Pages 17-21, January 2009

Short-Time In Vitro and In Vivo Precision of Direct Digital X-ray Radiogrammetry

Mari Hoff
- Department of Rheumatology, St. Olav's Hospital, Trondheim, Norway
- Norwegian University of Science and Technology, Trondheim, Norway
- Address correspondence to: Mari Hoff, MD, University Hospital of Trondheim, Norwegian University of Science and Technology, MTFS—Department of Neuroscience, Division of Rheumatology, NO-7489 Trondheim, Norway.
Alvilde Dhainaut
- Department of Rheumatology, St. Olav's Hospital, Trondheim, Norway
- Norwegian University of Science and Technology, Trondheim, Norway
Tore K. Kvien
- Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway
- Faculty of Medicine University of Oslo, Oslo, Norway
Kristina Forslind
- Section of Rheumatology, Helsingborgs Lasarett, Helsingborg, Sweden
Johan Kälvesten
- Sectra, Linköping, Sweden
Glenn Haugeberg
- Norwegian University of Science and Technology, Trondheim, Norway
- Department of Rheumatology, Sørlandet Hospital, Kristiansand S, Norway

Received 11 September 2008; received in revised form 20 October 2008; accepted 20 October 2008. published online 15 December 2008.

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 equipments, 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 equipments, in vitro precision ranged from 0.14% to 0.30%, expressed as coefficient of variations (CV%) and from 0.0012 to 0.0028g/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=0.0046g/cm², and least significant change (LSC%)=1.28%. The DXR-BMD for 1 of the X-ray equipments 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 equipments, and follow-up measurements should be performed with the same X-ray equipment.