数学法测量非碎裂性骨干骨折断端旋转度的CT实验研究

CT experimental study on rotation degrees of broken ends of bones of non-comminuted fracture measured by mathematical method

目的探讨在MSCT-MPR图像中,依据三角函数原理及勾股定理测量非碎裂性骨干骨折断端旋转度的可行性。方法将5根猪股骨折断后,分别将两断端固定在一个自制的模拟骨折旋转架上,在一侧断端旋转10°、30°、50°、70°、90°、110°、130°、150°、170°时,分别行MSCT薄层扫描、进行MPR重建,在图像中找到能体现两断端解剖对位的定位点,测量定位点在不同方位与中轴线的距离,依据三角函数原理及勾股定理计算出旋转度数,将计算数据与实际值对比分析。结果在以上9个旋转度下,5根猪股骨断端计算所得数据与实际值均较为接近,差值均在10°以内,差异无统计学意义(P>0.05)。结论在非碎裂骨干骨折MSCT-MPR图像中,可清楚显示定位点,依据数学原理可准确测量其旋转度。其计算过程通过程序化处理,简便、快捷,能为临床医生提供以往无法获得的折端旋转度信息,并为PACS软件工程师开发出骨折端旋转度测量工具提供理论支持。

Objective To explore the feasibility for measuring the rotation degrees of the broken ends of bones of non- comminuted fracture on the principle of trigonometric function and Pythagoras theorem in MSCT-MPR image. Methods Five pig femoral bones were broken off, and both broken ends were fixed to a self-made simulating fracture rotation frame, respectively;and then, the broken ends on one side were rotated to 10°、30°、50°、70°、90°、110°、130°、150°、and 170°, respectively; MSCT thin-layer scanning and MPR reconstruction were carried out,and the positioning points showing the anatomic directions of both broken ends were found in order to measure the distance between the positiorfing points and the central axes in different directions;lastly,the rotation degrees were calculated on the principle of trigonometric function and Pythagoras theorem, and a comparative analysis was made for the calculation results and the actual values. Results In the above nine rotation degrees, the calculation results of the five pig temoral bones were approximate to the actual values ,and the differences were all within 10°, having no significant difference （P 〉 0.05 ）. Conclusion In the MSCT-MPR images of bones of non-comminuted fracture, the positioning points may be shown clearly and the rotation degrees of the broken ends may be measured with mathematical method;the process of calculation may be processed by programs fast and easily,so as to provide information about the rotation degrees of the broken ends and theoretical support for PACS software engineer to develop tools to measure the rotation degrees of the broken ends of bones.