Digital X-ray radiogrammetry: a new appendicular bone densitometric methodwith high precision

The precision of any given method for measurement of bone mineral density ( BMD) is important in relation to the interpretation of repeated measurement s over time, e.g. to monitor the course of suspected osteoporosis or follow the effect of therapy. In the present study a new bone densitometer using the digital X-ray radiogrammetry (DXR) method (Pronosco X-posure System(TM) ) is investigated with respect to its short-term precision. The study was c arried out on two groups of females, one consisting of 20 women between the ages of 30 and 40, and the other of 20 post-menopausal women above the age of 64. The mean age of the premenopausal women was 35.2 years and the mean DXR BMD was 0.578 g cm(-2). The mean age of the post-menopausal women was 68.2 years and the mean DXR BMD was 0.489 g cm(-2). The short-term precisio n of the two groups was evaluated using the coefficient of variation (CV%) and corresponding 90% confidence intervals. The coefficient of variation in the premenopausal group was 0.68% with a 90% confidence interval of 0.57%- 0.83%. The coefficient of variation in the postmenopausal group was 0.61% w ith a 90% confidence interval of 0.52-0.75%. It can be concluded from the p resent study that the short-term in vivo precision error of the DXR method is low in both pre- and post-menopausal women. When the results of the stud y are compared to data reported in the literature, the performance of the D XR method seems to be at least equivalent with peripheral DXA.