Software and scan acquisition technique-related discrepancies in bone mineral assessment using dual-energy X-ray...

In adults, whole-body mineralization assessment by dual-energy X-ray absorptiometry can be affected by the densitometer and/or the software used. As there are no published data on neonates, the aim of this study was to evaluate the magnitude of such effects in growing preterm infants.

We analysed the absorptiometry results obtained from 44 preterm infants scanned at discharge and again 6 wk later using densitometers from the same manufacturer equipped with "Pediatric" (Group A, n = 24) or with "Infant" (Group B, n = 20) packages. Results of bone mineral content assessment were compared using an unpaired t-test and a linear regression analysis.

At the time of the first absorptiometry (body weight = 2119 +/- 144 g, n = 44), the bone mineral content was three times lower in Group A (10 +/- 3 g) than in Group B (29 +/- 4 g) (p < 0.001). Subsequently, on the second absorptiometry (body weight = 4037 +/- 236 g, n = 44) such significant differences in bone mineral content (A: 65 +/- 19 g, B: 66 +/- 9 g, p = 0.85) were no longer in evidence. The differences in bone mineral content were related to differences in analysis algorithms between the two programs, which can lead to an overestimation of bone mineral content accretion when two successive measurements are made using the "Pediatric"package.

Considering that significant differences in bone mineral assessment may depend upon which program is used, data previously collected in low birthweight infants using the "Pediatric" package should be analysed with caution. Data obtained using the "Pediatric" and "Infant" packages are not directly comparable. Careful validation studies of future densitometers and programs are required before their use in clinical paediatric studies.