Distal metacarpal bone mineral density by dual energy X-ray absorptiometry (DEXA) scan. Methodological investigation and application in rheumatoid arthritis.

Dual energy X-ray absorptiometry scanning was performed along the axis of the third metacarpal bone of the non-dominant hand and including metacarpal bones 2, 3, 4 and 5. The Bone Mineral Density (BMD) was calculated for the distal 1/4 of each metacarpal bone. Ten patients with seropositive, erosive rheumatoid arthritis (RA) and 10 healthy, sex- and age-matched persons were investigated twice. The average BMD in RA patients was 73.6% of the value found in normals. The coefficient of variation on double determinations (in patients and controls) was 0.9-3.0%. We suggest that dual energy X-ray absorptiometry scanning with the scanning procedure proposed here may be an important instrument for the quantification of disease progression.