Abrahamsen B, Gram J, Hansen T B, Beck-Nielsen H
Department of Medical Endocrinology M, Odense University Hospital, Denmark.
Bone. 1995 Mar;16(3):385-90. doi: 10.1016/8756-3282(94)00054-9.
Replacement of dual energy X-ray densitometry (DXA) equipment may be necessary in many labs with time, or new equipment may be added. In this context we compared patient scans between a Hologic QDR-1000W and a QDR-2000 (n = 29-43, depending on anatomic region) and between QDR-2000 single beam (SB) and fan beam (FB) modes (n = 40-62) as a quality control measure. A total of 83 subjects (79 females and four males) with a wide range of bone mineral densities (BMD) were studied. There was a linear relationship between results with the QDR-1000W and QDR-2000 in SB mode, and between SB and FB mode on the QDR-2000, but the magnitude of the coefficients and constants differed for the different anatomic regions. In SB mode the QDR-2000 underestimated whole body and forearm BMD by 3% relative to the QDR-1000W, even after cross calibration using a spine phantom. Femoral total BMD was slightly, but not significantly, underestimated. Thus, additional postanalysis correction had to be applied to forearm and whole-body scans. In FB with the QDR-2000, spine and whole-body BMD was underestimated by 3%, but femur total and neck BMD was overestimated by 2.2 and 2.8%, respectively, compared with SB scans on the same device. Soft-tissue composition with FB (enhanced analysis protocol) on the QDR-2000 differed greatly from that obtained using SB (standard protocol). Lean tissue mass was 4 kg lower and fat mass 4 kg higher in FB mode.(ABSTRACT TRUNCATED AT 250 WORDS)
随着时间推移，许多实验室可能需要更换双能X线骨密度仪（DXA）设备，或者增添新设备。在此背景下，我们将Hologic QDR - 1000W型与QDR - 2000型（根据解剖部位不同，n = 29 - 43）以及QDR - 2000型的单束（SB）和扇束（FB）模式（n = 40 - 62）下的患者扫描结果进行比较，作为一项质量控制措施。共研究了83名受试者（79名女性和4名男性），他们的骨矿物质密度（BMD）范围广泛。QDR - 1000W与QDR - 2000在SB模式下的结果之间，以及QDR - 2000上SB模式和FB模式的结果之间存在线性关系，但不同解剖部位的系数和常数大小有所不同。在SB模式下，即使使用脊柱模型进行交叉校准后，QDR - 2000相对于QDR - 1000W仍低估了全身和前臂的骨密度3%。股骨总骨密度略有低估，但不显著。因此，必须对前臂和全身扫描结果进行额外的分析后校正。在QDR - 2000的FB模式下，与同一设备的SB扫描相比，脊柱和全身骨密度低估了3%，但股骨总骨密度和颈部骨密度分别高估了2.2%和2.8%。QDR - 2000上FB模式（增强分析方案）的软组织成分与SB模式（标准方案）有很大差异。FB模式下瘦组织质量低4千克，脂肪质量高4千克。（摘要截断于250字）
