Lang T, Takada M, Gee R, Wu C, Li J, Hayashi-Clark C, Schoen S, March V, Genant H K
Osteoporosis Research Group, Department of Radiology, University of California-San Francisco, 94143-1250, U.S.A.
J Bone Miner Res. 1997 Jan;12(1):136-43. doi: 10.1359/jbmr.1997.12.1.136.
We have evaluated the Lunar Expert-XL for standard bone mineral densitometry (BMD) and for morphometric imaging of the spine in the lateral projection. The short-term precision in vitro of the Expert-XL for BMD measurements was 0.7% for the Hologic and European spine phantoms, and the long-term stability (15-month) measurements had a 1.1% coefficient of variation. The precision in vivo for three operators examining a group of 10 premenopausal women was 0.9-1.5% for lumbar spine (L2-L4), 1.7-2.2% for the femoral neck, and 0.9% for the total hip region of interest. For a group of nine postmenopausal women, the lumbar spine, femoral neck, and total femur precision ranges were 2.0-2.4, 1.2-2.9, and 1.6-1.7% respectively. For L2-L4, BMD comparison between the Expert-XL and DPX-L yielded a correlation coefficient of r = 0.98, a slope of 0.86, and an intercept of 0.139 g/cm2. The femoral neck results were r = 0.92, slope = 1.00, and intercept = 0.03 g/cm2. In an evaluation of the Expert-XL for lateral morphometry, we employed a group of 16 postmenopausal women. Comparison of vertebral dimensions between the Expert-XL and radiographic morphometry showed strong agreement (r = 0.97), but the interobserver variability for vertebral height was higher for the Expert-XL than for radiographs (3-5% vs. 1-2%). In a subset of four women who had repeat scans, the interscan precision for measuring vertebral dimensions was 1.9, 4.1, and 43% for the L1-L4, T12-T8, and T7-T5 levels respectively. In the Expert-XL images, it was possible to identify clearly L4-T4 in 10 of 16 patients and L4-T6 in 15 of 16, indicating potential utility for vertebral fracture prescreening.
我们评估了Lunar Expert-XL用于标准骨密度测定（BMD）以及脊柱侧位形态计量成像的性能。Expert-XL在体外进行BMD测量时，对于Hologic和欧洲脊柱模型的短期精密度为0.7%，长期稳定性（15个月）测量的变异系数为1.1%。三名操作人员对一组10名绝经前女性进行体内测量时，腰椎（L2-L4）的精密度为0.9%-1.5%，股骨颈为1.7%-2.2%，全髋感兴趣区域为0.9%。对于一组9名绝经后女性，腰椎、股骨颈和全股骨的精密度范围分别为2.0%-2.4%、1.2%-2.9%和1.6%-1.7%。对于L2-L4，Expert-XL与DPX-L之间的BMD比较得出相关系数r = 0.98，斜率为0.86，截距为0.139 g/cm²。股骨颈的结果为r = 0.92，斜率 = 1.00，截距 = 0.03 g/cm²。在对Expert-XL进行侧位形态计量评估时，我们纳入了一组16名绝经后女性。Expert-XL与X线形态计量之间的椎体尺寸比较显示出高度一致性（r = 0.97），但Expert-XL的观察者间椎体高度变异性高于X线片（3%-5%对1%-2%）。在4名进行重复扫描的女性子集中，L1-L4、T12-T8和T7-T5水平测量椎体尺寸的扫描间精密度分别为1.9%、4.1%和43%。在Expert-XL图像中，16名患者中有10名能够清晰识别L4-T4，15名能够清晰识别L4-T6，表明其在椎体骨折预筛查方面具有潜在用途。
