Comparison of two Hologic DXA systems (QDR 1000 and QDR 4500/A)
Comparison of two Hologic DXA systems (QDR 1000 and QDR 4500/A)
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DOI：
10.1259/bjr.70.835.9245885
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发表时间：
1997-07-01
影响因子：
2.6
通讯作者：
BasseCathalinat, B
中科院分区：
文献类型：
--
作者：
Barthe, N;Braillon, P;BasseCathalinat, B
如果遵循制造商的建议和质量控制（QC）程序，双能X射线吸收法（DXA）可以可靠地测量骨矿物质含量。使用几种体模（Hologic拟人脊柱体模、Groupe de Recherche et d 'Informations sur les Osteoporoses（GRIO）测试对象和欧洲半拟人体模）评价体外两种DXA器械的再现性、线性、准确度和空间分辨率。这些参数也进行了评价，在体内从120名志愿者患者进行的测量。结果发现，当一台设备（单光束单探测器QDR 1000）被另一台设备（扇形光束多探测器QDR 4500/A）替换时，本文所述的新程序组合可确保在同一患者连续使用两台设备时保持DXA研究结果的准确性。为了研究临床情况下可能的反应，还评价了骨环境（软组织和脂肪组织）的影响。在两种系统中，确定了相似的性能（体外变异系数为0.5%）。在极端骨密度值，线性略有差异，以及精度和空间分辨率的差异。使用两种系统对120名志愿者进行腰椎和股骨颈测量，两次测量均在同一天进行。相应的骨矿物质密度（BMD）值高度相关（腰椎r（2）= 0.985，股骨颈r（2）= 0.948），每个解剖部位的平均BMD差异分别为0.68%和0.37%。虽然很小，但这些差异增加了该方法的精度误差，接近1%。必须获得校准曲线，以便两种器械可同等用于常规临床研究。我们的结论是，当DXA系统更换为新系统时，必须严格遵守适当的QC程序。
Bone mineral content is reliably measured by dual energy X-ray absorptiometry (DXA), if manufacturers' recommendations and quality control (QC) procedures are followed. Several phantoms (Hologic anthropomorphic spine phantom, the Groupe de Recherche et d'Informations sur les Osteoporoses (GRIO) test objects and the European semi-anthropomorphic phantoms) were used to evaluate reproducibility, linearity, accuracy and spatial resolution of two DXA devices in vitro. These parameters were also evaluated in vivo from measurements performed on 120 volunteer patients. It was found that when one device (a single beam monodetector QDR 1000) is replaced by another (a fan beam multidetector QDR 4500/A), the novel combination of procedures described here, ensures that the accuracy of DXA study results is maintained when both devices are used in succession for the same patient. To study the possible responses in clinical situations, the influence of bone environment (soft and adipose tissues) was also evaluated. In both systems, similar performances (in vitro coefficients of variation of 0.5%) were established. At extreme bone density values, slight differences in linearity were found, as well as differences in accuracy and spatial resolution. Lumbar spine and femoral neck measurements were performed with both systems in 120 volunteers, both measurements being made on the same day. The corresponding bone mineral density (BMD) values were highly correlated (r(2) = 0.985 for lumbar spine and 0.948 for the femoral neck), and the mean BMD differences were 0.68% and 0.37% for each anatomical site, respectively. Although small, these differences add to the precision error of the method, which is near 1%. A calibration curve has to be obtained in order that both devices can be equally used in regular clinical study. We concluded that when a DXA system is replaced by a new one, appropriate QC procedures must be strictly observed.