Hui S L, Gao S, Zhou X H, Johnston C C, Lu Y, Glüer C C, Grampp S, Genant H
Department of Medicine, Indiana University School of Medicine, Indianapolis, USA.
J Bone Miner Res. 1997 Sep;12(9):1463-70. doi: 10.1359/jbmr.1997.12.9.1463.
The International Dual-Photon X-Ray Absorptiometry (DXA) Standardization Committee (IDSC) conducted a cross-calibration study among three models of DXA machines from three different manufacturers. In that study, 100 subjects were scanned on all three machines. A set of equations were derived to convert bone mineral density (BMD) on each machine to a "standardized BMD" (sBMD) such that sBMD from the same subject derived from different machines would be approximately the same. In a reanalysis of the cross-calibration data, we showed that the conversion method used in the IDSC study did not achieve several optimal properties desirable in such conversions. We derived new conversion equations to sBMD based on minimizing differences among sBMD from the three machines. More important is that the new conversions have no residual bias that was present in the IDSC conversions. The performance of the methods were compared on the cross-calibration data as well as an external data set. We conclude that the IDSC conversions are adequate for clinical use on other machines worldwide, but that researchers should standardize their own machines in a laboratory using the new method.
国际双能X线吸收法（DXA）标准化委员会（IDSC）在来自三个不同制造商的三种型号的DXA机器之间进行了一项交叉校准研究。在该研究中，对100名受试者在所有三台机器上进行了扫描。推导了一组方程，将每台机器上的骨密度（BMD）转换为“标准化骨密度”（sBMD），以使来自不同机器的同一受试者的sBMD大致相同。在对交叉校准数据的重新分析中，我们表明IDSC研究中使用的转换方法未达到此类转换中理想的几个最佳特性。我们基于最小化三台机器的sBMD之间的差异，推导了新的sBMD转换方程。更重要的是，新的转换没有IDSC转换中存在的残留偏差。在交叉校准数据以及外部数据集上比较了这些方法的性能。我们得出结论，IDSC转换足以在全球其他机器上用于临床，但研究人员应在实验室中使用新方法对自己的机器进行标准化。
