From the Department of Radiology, Center for Musculoskeletal Care (G.C.), Osteoporosis Center, Hospital for Joint Diseases (S.H.), Department of Orthopaedic Surgery, Hospital for Joint Diseases (K.A.E.), and Department of Radiology, Center for Biomedical Imaging (G.C., R.B., C.M.D., J.S.B., R.R.R.), NYU Langone Medical Center, 550 First Avenue, New York, NY 10016; and Department of Radiology, University of Pennsylvania School of Medicine, 3400 Spruce Street, Philadelphia, PA (C.S.R.).
Radiology. 2014 Aug;272(2):464-74. doi: 10.1148/radiol.14131926. Epub 2014 Apr 2.
To determine the feasibility of using finite element analysis applied to 3-T magnetic resonance (MR) images of proximal femur microarchitecture for detection of lower bone strength in subjects with fragility fractures compared with control subjects without fractures.
This prospective study was institutional review board approved and HIPAA compliant. Written informed consent was obtained. Postmenopausal women with (n = 22) and without (n = 22) fragility fractures were matched for age and body mass index. All subjects underwent standard dual-energy x-ray absorptiometry. Images of proximal femur microarchitecture were obtained by using a high-spatial-resolution three-dimensional fast low-angle shot sequence at 3 T. Finite element analysis was applied to compute elastic modulus as a measure of strength in the femoral head and neck, Ward triangle, greater trochanter, and intertrochanteric region. The Mann-Whitney test was used to compare bone mineral density T scores and elastic moduli between the groups. The relationship (R(2)) between elastic moduli and bone mineral density T scores was assessed.
Patients with fractures showed lower elastic modulus than did control subjects in all proximal femur regions (femoral head, 8.51-8.73 GPa vs 9.32-9.67 GPa; P = .04; femoral neck, 3.11-3.72 GPa vs 4.39-4.82 GPa; P = .04; Ward triangle, 1.85-2.21 GPa vs 3.98-4.13 GPa; P = .04; intertrochanteric region, 1.62-2.18 GPa vs 3.86-4.47 GPa; P = .006-.007; greater trochanter, 0.65-1.21 GPa vs 1.96-2.62 GPa; P = .01-.02), but no differences in bone mineral density T scores. There were weak relationships between elastic moduli and bone mineral density T scores in patients with fractures (R(2) = 0.25-0.31, P = .02-.04), but not in control subjects. CONCLUSION Finite element analysis applied to high-spatial-resolution 3-T MR images of proximal femur microarchitecture can allow detection of lower elastic modulus, a marker of bone strength, in subjects with fragility fractures compared with control subjects. MR assessment of proximal femur strength may provide information about bone quality that is not provided by dual-energy x-ray absorptiometry.
通过应用于 3T 磁共振（MR）图像的有限元分析来检测脆性骨折患者与无骨折对照者的股骨近端微观结构的较低骨强度，确定其可行性。
该前瞻性研究获得了机构审查委员会的批准并符合 HIPAA 规定。获得了书面知情同意。纳入（n=22）和未纳入（n=22）脆性骨折的绝经后妇女，按年龄和体重指数进行匹配。所有患者均进行了标准的双能 X 线吸收法检查。通过使用 3T 高空间分辨率三维快速低角度激发序列获得股骨近端微观结构图像。应用有限元分析计算骨强度的弹性模量作为股骨头和颈部、Ward 三角区、大转子和转子间区的测量值。使用 Mann-Whitney 检验比较两组之间的骨密度 T 评分和弹性模量。评估了弹性模量与骨密度 T 评分之间的关系（R²）。
与对照组相比，骨折组所有股骨近端区域（股骨头 8.51-8.73GPa 比 9.32-9.67GPa；P=0.04；股骨颈 3.11-3.72GPa 比 4.39-4.82GPa；P=0.04；Ward 三角区 1.85-2.21GPa 比 3.98-4.13GPa；P=0.04；转子间区 1.62-2.18GPa 比 3.86-4.47GPa；P=0.006-0.007；大转子区 0.65-1.21GPa 比 1.96-2.62GPa；P=0.01-0.02）的弹性模量均较低，但骨密度 T 评分无差异。在骨折患者中，弹性模量与骨密度 T 评分之间存在弱相关性（R²=0.25-0.31，P=0.02-0.04），而在对照组中则无相关性。
应用于 3T 高空间分辨率磁共振图像的有限元分析可以检测到脆性骨折患者与对照组相比，其股骨近端微观结构的较低弹性模量，这是骨强度的标志物。与双能 X 线吸收法相比，磁共振评估股骨近端强度可提供有关骨质量的信息。
