骨质疏松髋部骨折区影像学参数与骨微结构关系研究

ANALYSIS OF CORRELATION BETWEEN TRABECULAR MICROSTRUCTURE AND CLINICAL IMAGING PARAMETERS IN FRACTURE REGION OF OSTEOPOROTIC HIP

目的分析骨质疏松髋部骨折区骨微结构参数与影像学参数之间的相关性，为影像学间接评估髋部松质骨微结构变化提供依据。 方法以2012年6月－2013年1月收治的16例低能量创伤致股骨颈骨折并行人工髋关节置换的老年患者作为试验组；以同期5例骨盆骨折青年患者作为对照组。对照组行髋部薄层CT扫描，Mimics10.01软件分析股骨近端松质骨体积/髓腔体积（cancellous bone volume/marrow cavity volume，CV/MV）；试验组行健侧髋部薄层CT扫描及骨密度检测，并于置换术中切取股骨颈张力侧松质骨，行Micro-CT扫描分析微结构参数，包括骨体积分数（bone volume fraction，BV/TV）、骨小梁数量（trabecular number，Tb.N）、骨小梁距离（trabecular spacing，Tb.Sp）、骨小梁厚度（trabecular thickness，Tb.Th）、连接密度（connect density，Conn.D）、结构模型指数（structure model index，SMI）。分析影像学参数及骨微结构参数间的相关性。 结果试验组骨密度值为0.491～0.698 g/ cm2，平均0.601 g/ cm2；根据世界卫生组织（WHO）推荐的骨质疏松诊断标准，其中10例为骨质疏松，6例为骨量减少。试验组髋部CV/MV为0.670 1 ± 0.102 0，显著低于对照组的 0.885 0 ± 0.089 1 （t= —4.567，P=0.000）。试验组CV/MV与骨微结构参数BV/TV、Tb.Th、SMI相关（P 〈 0.05），与Tb.N、Tb.Sp、Conn.D不相关（P 〉 0.05）；BV/TV与Tb.Th、Tb.N、Tb.Sp、SMI相关（P 〈 0.05），与Conn. D不相关（P=0.075）；骨密度值与各骨微结构参数之间均无相关性（P 〉 0.05）。 结论骨质疏松患者股骨近端CT参数CV/MV明显降低，并且与松质骨的BV/TV、Tb.Th、SMI存在相关性，该指标能一定程度上反映骨微结构变化；而股骨颈骨密度与骨微结构参数间无相关性。

Objective To analyze the correlation between the trabecular microstructure and the clinical imaging parameters in the fracture region of osteoporotic hip so as to provide a simple method to evaluate the trabecular microstructure by a non-invasive way. Methods Between June 2012 and January 2013, 16 elderly patients with femoral neck fracture underwent hip arthroplasty were selected as the trial group; 5 young patients with pelvic fracture were selected as the control group. The hip CT examination was done, and cancellous bone volume/marrow cavity volume （CV/MV） was analyzed with Mimics 10.01 software in the control group. The CT scan and bone mineral density （BMD） measurement were performed on normal hips of the trial group, and cuboid specimens were gained from the femoral necks at the place of the tensional trabeculae to evaluate the trabecular microstructure parameters by Micro-CT, including bone volume fraction （BV/TV）, trabecular number （Tb. N）, trabecular spacing （Tb.Sp）, trabecular thickness （Tb.Th）, connect density （Conn.D）, and structure model index （SMI）. The correlation between imaging parameters and microstructure parameters was analyzed. Results In the trial group, the BMD value was 0.491-0.698 g/cm2 （mean, 0.601 g/cm2）; according to World Health Organization （WHO） standard, 10 cases were diagnosed as having osteoporosis, and 6 cases as having osteopenia. The CV/MV of the trial group （0.670 1 ± 0.102 0） was significantly lower than that of the control group （0.885 0 ± 0.089 1） （t= — 4.567, P=0.000）. In the trial group, CV/MV had correlation with BV/TV, Tb.Th, and SMI （P 〈 0.05）; however, CV/MV had no correlation with Tb.N, Tb.Sp, or Conn.D （P 〉 0.05）. BV/TV had correlation with Tb.Th, Tb.N, Tb.Sp, and SMI （P 〈 0.05）, but it had no correlation with Conn.D （P=0.075）. There was no correlation between BMD and microstructure parameters （P 〉 0.05）. Conclusion CV/MV obviously decreases in the osteoporotic hip, and there is a correlation between CV/MV and the microstructure parameters of BV/TV, Tb.Th, and SMI, to some extent, which can reflect the variety of the microstructure of the trabeculae. There is no correlation between BMD of femoral neck and microstructure parameters.