Abstract
Background: Quantitative bone measures, especially at the hand have been proposed as a new outcome measure in rheumatoid arthritis (RA) and is also, as hand bone loss in RA associated with disease activity, physical function and bone damage. The precision of any method is crucial for assessment of differences between groups and for changes over time on both a group level and especially on an individual level.
Objectives: The objectives for this study were to assess hand BMD in-vivo short term reproducibility for DXR and DEXA.
Material and Methods: 28 healthy individuals underwent DEXA (Lunar Expert) duplicate hand scans and DXR (Pronosco X-posure System) (using duplicate hand radiographs). 39 RA patients underwent DXR. The Long-term spine phantom CV was 0.80% for DEXA and 0.25% for DXR. The DXR CV for mean both hands was 0, 28% for healthy individuals and 0,46% for RA patients. The DXA CV for mean both hands was 0, 76 for healthy individuals. Percentage SDD was calculated as 0.79% for DXR healthy individuals, 1.30% for DXR RA patients and 2.15% for DEXA healthy individuals.
Results:The short-term in-vivo precision is acceptable for both methods however superior for DXR. The mean values of both hands should be used to achieve the best precision. The DXR precision is dependent on the BMD level of the examined individuals.