X-ray image of the hand is the most used technique to estimate bone age in children. For the analysis of bone mineral density using DXA in children, bone age may help to adjust such measurement in some cases. During image acquisition in DXA, an anteroposterior image of the hand may be acquired and used to evaluate bone age but few studies have evaluated the agreement between conventional X-ray and DXA images. The aim of the study was to determine bone age estimation agreement between conventional X-ray images and DXA in children and adolescents aged 5 to 16 years of age. We performed an analytical cross-sectional study of 711 healthy subjects. Subject´s bone age, both in conventional X-ray, and DXA images were read independently by two expert evaluators blinded for chronological age. Intraobserver and inter-observer reproducibility were evaluated using Intraclass Correlation Coefficient (ICC), and the agreement between bone age estimations made by both evaluators was analyzed using ICC and Bland-Altman analysis. General agreement between techniques measured through ICC was 0.99 with a mean difference of 6 months between techniques being older the ages obtained by DXA. The agreement limits were around ±2 years, which means that 95% of all differences between techniques were covered within this range. We found a high level of ICC agreement in bone age readings from X-ray and DXA images although we observed overestimation of bone age measurements in DXA. Differences between techniques were greater in women than in men, especially at the ages corresponding to puberty. Bone age measurement in DXA images appears not to be reliable; hence it should be suggested to perform conventional radiography of the hand to assess bone age taking into account that X-ray images have better resolution.

手的 X 射线图像是估计儿童骨龄最常用的技术。对于使用 DXA 分析儿童骨矿物质密度，骨龄在某些情况下可能有助于调整此类测量。在 DXA 的图像采集过程中，可以采集手的前后位图像并用于评估骨龄，但很少有研究评估传统 X 射线和 DXA 图像之间的一致性。该研究的目的是确定骨龄估计5 至 16 岁儿童和青少年的常规 X 射线图像和 DXA 之间的一致性。我们对 711 名健康受试者进行了分析性横断面研究。受试者的骨龄，包括常规 X 射线和 DXA 图像，由两位对实际年龄不知情的专家评估员独立读取。使用组内相关系数 (ICC) 评估观察者内和观察者间的再现性，并使用 ICC 和 Bland-Altman 分析分析两个评估者做出的骨龄估计之间的一致性。通过 ICC 测量的技术之间的一般一致性为 0.99，技术之间的平均差异为 6 个月，比 DXA 获得的年龄大。协议限制约为 ±2 年，这意味着该范围内涵盖了技术之间所有差异的 95%。尽管我们观察到 DXA 中的骨龄测量值被高估，但我们发现 X 射线和 DXA 图像的骨龄读数具有高度的 ICC 一致性。女性的技术差异大于男性，尤其是在与青春期相对应的年龄段。DXA 图像中的骨龄测量似乎不可靠；因此，考虑到 X 射线图像具有更好的分辨率，应该建议对手进行常规 X 线摄影以评估骨龄。