Can digital X-ray radiogrammetry be an alternative for dual-energy X-ray absorptiometry in the diagnosis of secondary low bone quality in children?

Bone quality in children is generally measured with dual-energy X-ray absorptiometry (DXA). Digital X-ray radiogrammetry (DXR) uses BoneXpert to measure cortical bone quality on hand radiographs. This prospective study compared DXR and DXA results in children with high probability of secondary low bone quality, defined as DXA of the lumbar spine (DXA) Z-score ≤ - 2.0. One hundred one children underwent both DXA and DXR assessment. DXAZ-scores were also adjusted for bone age. DXR Z-scores were compared with both DXAZ-scores, using Pearson correlations, Bland-Altman analysis, and sensitivity-specificity analysis. Mean bone age, DXR, and both DXA Z-scores were significantly impaired. Pearson correlation coefficients were significant between DXR Z-scores and both DXAZ-scores 0.507-0.564 (p < 0.001). Bland-Altman analysis showed a mean difference of 0.05-0.48 between DXR and both DXA Z-scores and showed more than 90% similarity for both DXAZ-scores ≤ - 2.0. DXR had a sensitivity of 67-71% and specificity of 77-83% compared to both DXAZ-scores.Conclusion: DXR correlates well with as well DXA as bone age-adjusted DXAZ-scores and shows good agreement with as well DXA as bone age-adjusted DXAZ-scores ≤ - 2.0. DXR shows best results when compared with DXAZ-scores. What is Known: • Digital X-ray radiogrammetry (DXR) may correlate well with dual-energy X-ray absorptiometry (DXA) in pediatric, adolescent, and adult patients. • DXR is a feasible method for assessment of bone quality in children. What is New: • This is the first prospective study in children with suspected secondary low bone quality that illustrates correlation between DXR and bone age-adjusted DXA Z-scores and that shows good agreement between DXR and DXA as bone age-adjusted DXA Z-scores ≤ -2.0. • Our results suggest DXR to be a good alternative for DXA for determining low bone quality.