Half of the women who sustain a hip fracture would not qualify for osteoporosis treatment based on current DXA-estimated bone mineral density criteria. Therefore, a better approach is needed to determine if an individual is at risk of hip fracture from a fall. The objective of this study was to determine the association between radiation-free MRI-derived bone strength and strain simulations compared to results from direct mechanical testing of cadaveric femora. Imaging was conducted on a 3-Tesla MRI scanner using two sequences: one balanced steady-state free precession sequence with 300 μm isotropic voxel size and one spoiled gradient echo with anisotropic voxel size of 234 × 234 × 1500 μm. Femora were dissected free of soft-tissue and 4350-ohm strain-gauges were securely applied to surfaces at the femoral shaft, inferior neck, greater trochanter, and superior neck. Cadavers were mechanically tested with a hydraulic universal test frame to simulate loading in a sideways fall orientation. Sideways fall forces were simulated on MRI-based finite element meshes and bone stiffness, failure force, and force for plastic deformation were computed. Simulated bone strength metrics from the 300 μm isotropic sequence showed strong agreement with experimentally obtained values of bone strength, with stiffness (r = 0.88, p = 0.0002), plastic deformation point (r = 0.89, p < 0.0001), and failure force (r = 0.92, p < 0.0001). The anisotropic sequence showed similar trends for stiffness, plastic deformation point, and failure force (r = 0.68, 0.70, 0.84; p = 0.02, 0.01, 0.0006, respectively). Surface strain-gauge measurements showed moderate to strong agreement with simulated magnitude strain values at the greater trochanter, superior neck, and inferior neck (r = -0.97, -0.86, 0.80; p ≤0.0001, 0.003, 0.03, respectively). The findings from this study support the use of MRI-based FE analysis of the hip to reliably predict the mechanical competence of the human femur in clinical settings.

中文翻译：

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与机械测试相比，基于 MRI 的股骨近端强度评估

根据目前 DXA 估计的骨矿物质密度标准，有一半的髋部骨折女性没有资格接受骨质疏松症治疗。因此，需要一种更好的方法来确定一个人是否有因跌倒而导致髋部骨折的风险。本研究的目的是确定无辐射 MRI 衍生的骨强度与应变模拟之间的关联，与尸体股骨的直接机械测试结果相比。使用两个序列在​​ 3-Tesla MRI 扫描仪上进行成像：一个具有 300 μm 各向同性体素大小的平衡稳态自由进动序列和一个具有 234 × 234 × 1500 μm 各向异性体素大小的破坏梯度回波。解剖股骨，去除软组织，将 4350 欧姆应变计牢固地应用于股骨干、下颈、大转子、和优越的脖子。使用液压通用测试框架对尸体进行机械测试，以模拟侧向坠落方向的负载。在基于 MRI 的有限元网格上模拟侧向坠落力，并计算骨骼刚度、破坏力和塑性变形力。来自 300 μm 各向同性序列的模拟骨强度指标与实验获得的骨强度值非常一致，包括刚度 (r = 0.88, p = 0.0002)、塑性变形点 (r = 0.89, p < 0.0001) 和破坏力 ( r = 0.92，p < 0.0001）。各向异性序列显示出类似的刚度、塑性变形点和破坏力趋势（分别为 r = 0.68、0.70、0.84；p = 0.02、0.01、0.0006）。表面应变测量显示与模拟的大转子、上颈和下颈的应变值中度至强一致（r = -0.97、-0.86、0.80；分别为 p ≤0.0001、0.003、0.03）。这项研究的结果支持使用基于 MRI 的髋关节有限元分析来可靠地预测临床环境中人类股骨的机械能力。