School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada.
Department of Mechanical Engineering, McMaster University, Hamilton, ON, Canada.
Proc Inst Mech Eng H. 2024 Jan;238(1):90-98. doi: 10.1177/09544119231214651. Epub 2023 Dec 19.
The diagnosis of osteoporosis using Dual-energy X-ray Absorptiometry (DXA) relies on accurate hip scans, whereby variability in measurements may be introduced by altered patient positioning, as could occur with repeated scans over time. The goal herein was to test how altered postures affect diagnostic metrics (i.e., standard clinical metrics and a newer image processing tool) for femur positioning. A device was built to support cadaveric femurs and adjust their orientation in 3° increments in flexion and internal/external rotation. Seven isolated femurs were scanned in six flexion postures (0° (neutral) to 15° of flexion) and eleven rotational postures (15° external to 15° internal rotation) while collecting standard clinical DXA-based measures for each scan. The fracture risk tool was applied to each scan to calculate fracture risk. Two separate one-way repeated measures ANOVAs (α = 0.05) were performed on the DXA-based measures and fracture risk prediction output. Flexion had a significant effect on T-score, Bone Mineral Density (BMD), and Bone Mineral Content (BMC), but not area, at angles greater than 12°. Internal and external rotation did not have a significant effect on any clinical metric. Fracture risk (as assessed by the image processing tool) was not affected by either rotation mode. Overall, this suggests clinicians can adjust patient posture to accommodate discomfort if deviations are less than 12 degrees, and the greatest care should be taken in flexion. Furthermore, the tool is relatively insensitive to postural adjustments, and as such may be a good option for tracking risk over repeated patient scans.
使用双能 X 射线吸收法（DXA）诊断骨质疏松症依赖于准确的髋关节扫描，而随着时间的推移，重复扫描可能会导致患者体位的改变，从而导致测量结果的变异性。本研究旨在测试体位改变如何影响股骨定位的诊断指标（即标准临床指标和一种新的图像处理工具）。为此，我们设计了一种设备来支撑尸体股骨，并以 3°的增量调整其在屈曲和内/外旋方向的方向。将 7 个离体股骨分别在 6 个屈曲位置（0°（中立）至 15°屈曲）和 11 个旋转位置（15°外旋至 15°内旋）下进行扫描，同时收集每个扫描的标准临床 DXA 测量值。将骨折风险工具应用于每个扫描，以计算骨折风险。对基于 DXA 的测量值和骨折风险预测结果分别进行了两次独立的单向重复测量方差分析（α=0.05）。在角度大于 12°时，屈曲对 T 评分、骨密度（BMD）和骨矿物质含量（BMC）有显著影响，但对面积没有影响。内旋和外旋对任何临床指标都没有显著影响。骨折风险（由图像处理工具评估）不受旋转模式的影响。总体而言，如果偏差小于 12 度，临床医生可以调整患者体位以适应不适，而在屈曲时应格外小心。此外，该工具对体位调整相对不敏感，因此可能是在重复患者扫描时跟踪风险的良好选择。
