DXA Unit, Carnegie Research Institute, Leeds Metropolitan University, Headingley Campus, Leeds, UK.
J Clin Densitom. 2010 Oct-Dec;13(4):413-7. doi: 10.1016/j.jocd.2010.06.002. Epub 2010 Aug 12.
Knowledge of precision is integral to the monitoring of bone mineral density (BMD) changes using dual-energy X-ray absorptiometry (DXA). We evaluated the precision for bone measurements acquired using a GE Lunar iDXA (GE Healthcare, Waukesha, WI) in self-selected men and women, with mean age of 34.8 yr (standard deviation [SD]: 8.4; range: 20.1-50.5), heterogeneous in terms of body mass index (mean: 25.8 kg/m(2); SD: 5.1; range: 16.7-42.7 kg/m(2)). Two consecutive iDXA scans (with repositioning) of the total body, lumbar spine, and femur were conducted within 1h, for each subject. The coefficient of variation (CV), the root-mean-square (RMS) averages of SDs of repeated measurements, and the corresponding 95% least significant change were calculated. Linear regression analyses were also undertaken. We found a high level of precision for BMD measurements, particularly for scans of the total body, lumbar spine, and total hip (RMS: 0.007, 0.004, and 0.007 g/cm(2); CV: 0.63%, 0.41%, and 0.53%, respectively). Precision error for the femoral neck was higher but still represented good reproducibility (RMS: 0.014 g/cm(2); CV: 1.36%). There were associations between body size and total-body BMD and total-hip BMD SD precisions (r=0.534-0.806, p<0.05) in male subjects. Regression parameters showed good association between consecutive measurements for all body sites (r(2)=0.98-0.99). The Lunar iDXA provided excellent precision for BMD measurements of the total body, lumbar spine, femoral neck, and total hip.
使用双能 X 射线吸收法（DXA）监测骨密度（BMD）变化时，对精度的了解至关重要。我们评估了在平均年龄为 34.8 岁（标准差 [SD]：8.4；范围：20.1-50.5）的自选择男性和女性中，使用通用电气 Lunar iDXA（通用电气医疗保健公司，威斯康星州沃基肖）获得的骨骼测量的精密度。这些人在体重指数（BMI）方面存在异质性（平均值：25.8 kg/m²；SD：5.1；范围：16.7-42.7 kg/m²）。每位受试者在 1 小时内连续两次进行全身、腰椎和股骨的 iDXA 扫描（重新定位）。计算了变异系数（CV）、重复测量标准差的均方根（RMS）平均值和相应的 95%最小有意义变化。还进行了线性回归分析。我们发现 BMD 测量具有很高的精度，特别是对于全身、腰椎和全髋的扫描（RMS：0.007、0.004 和 0.007 g/cm²；CV：0.63%、0.41%和 0.53%）。股骨颈的精度误差较高，但仍具有良好的可重复性（RMS：0.014 g/cm²；CV：1.36%）。在男性受试者中，身体大小与全身 BMD 和全髋 BMD SD 精度之间存在相关性（r=0.534-0.806，p<0.05）。回归参数显示所有身体部位的连续测量之间具有良好的相关性（r²=0.98-0.99）。Lunar iDXA 为全身、腰椎、股骨颈和全髋的 BMD 测量提供了出色的精度。
