Spine Trabecular Bone Score Precision, a Comparison Between GE Lunar Standard and High-Resolution Densitometers

Trabecular bone score (TBS) is related to microarchitecture and fracture risk independently of bone mineral density (BMD) and clinical risk factors. Widespread clinical TBS use requires documentation of reproducibility and ideally comparability across scanners. This study evaluated TBS reproducibility and explored differences between Lunar Prodigy and iDXA densitometers. Reproducibility was assessed from replicate scans in 210 men and women participating in various dual-energy X-ray absorptiometry (DXA) precision assessments. iDXA-to-Prodigy comparability was evaluated using 155 participants from 3 study groups. L1-L4 BMD and TBS precision was similar on iDXA and Prodigy (BMD coefficient of variation = 1.9% and 1.5% and TBS coefficient of variation = 1.4% and 1.6%, respectively). Precision did not differ between men and women; however, between-technologist differences (p < 0.05) of similar magnitude were observed for both BMD and TBS. Prodigy-to-Prodigy TBS values were highly correlated (R(2) = 0.85 with bias of -0.010 TBS units). Agreement was less robust comparing Prodigy with iDXA instruments (TBS R(2): 0.72-0.81 with biases of 0.012-0.034 TBS units). In conclusion, TBS precision is comparable to that of BMD and does not differ between men and women. Additionally, in these cohorts, slight TBS differences were observed between iDXA and Prodigy scans. These data suggest a potential difference between densitometer models perhaps due to higher iDXA image resolution.