Early metacarpal bone mineral density loss using digital x-ray radiogrammetry and 3-tesla wrist MRI in established rheumatoid arthritis: a longitudinal one-year observational study.
Rastogi A., Algulin J., Mangat P., Lim AKP., Satchithananda K., Hajnal JV., Taylor PC.
Objectives. Early change in rheumatoid arthritis (RA) is characterised by periarticular osteopenia. We investigated the relationship of early metacarpal digital X-ray radiogrammetry bone mineral density (DXR-BMD) change rate (RC-BMD, mg/cm(2)/month) to longitudinal changes in hand and feet radiographic and wrist MRI scores over 1 year. Materials and Methods. 10 RA patients completed the study and had wrist 3T-MRI and hand and feet X-rays at various time points over 1 year. MRI was scored by RAMRIS, X-ray was done by van der Heijde modified Sharp scoring, and RC-BMD was analysed using dxr-online. Results. There was good correlation amongst the two scorers for MRI measures and ICC for erosions: 0.984, BME: 0.943, and synovitis: 0.657. Strong relationships were observed between RC-BMD at 12-week and 1-year change in wrist marrow oedema (BME) (r = 0.78, P = 0.035) but not with erosion, synovitis, or radiographic scores. Conclusion. Early RC-BMD correlates with 1-year wrist BME change, which is a known predictor of future erosion and joint damage. However, in our pilot study, early RC-BMD did not show relationships to MRI erosion or radiographic changes over 1 year. This may reflect a slower kinetic in the appearance of MRI/radiographic erosions, generating the hypothesis that RC-BMD may be a more sensitive and early structural prognostic marker in RA follow-up.