Inter-scanner variability in bone mineral density and T-score measurements: A comparison of Stratos, Lunar, and...

Dual-energy X-ray absorptiometry (DXA) is the gold standard for assessing bone mineral density (BMD) and diagnosing osteoporosis (OP). However, variation in DXA scanner measurements may affect clinical interpretation. This study compared variability in BMD and T-score among DXA scanners in widespread clinical usage: Stratos DR, Lunar DPX- NT and Osteosys Primus.

A retrospective analysis was conducted with 64 patients who underwent BMD measurements using Stratos, Lunar, and Osteosys scanners within 1 year at the same hospital. Paired comparisons of T-score and BMD were made between devices. Intra-class correlation coefficients (ICCs) and a Bland-Altman analysis were used for device reliability and device-to-device biases. The McNemar test was used to compare differences in OP and severe OP classifications.

The mean age of participants was 65.2 ± 9.83 years (range, 40-83). ICCs for T-scores were 0.782 between Stratos and Lunar and 0.791 between Stratos and Osteosys, indicating strong inter-device reliability. BMD measurements showed ICCs ranging from 0.317 (L1) to 0.956 (femur total). Bland-Altman plots revealed minor biases between scanners, with a slight positive bias for femoral neck T-scores. No significant differences in OP and severe OP diagnoses were found across the scanners.

DXA scanners showed substantial concordance in T-score and BMD, particularly in femoral measurements. The slight differences between these measurements did not have a major effect on OP diagnosis. Greater variability in lumbar spine results warrants caution. Further studies should aim to minimize inter-scanner differences and assess their long-term clinical implications.