Hildebrand TOR, Rüegsegger PETER
Institute for Biomedical Engineering, University of Zürich and Swiss Federal Institute of Technology (ETH), Moussonstrasse 18, CH-8044 Zürich, Switzerland.
Comput Methods Biomech Biomed Engin. 1997;1(1):15-23. doi: 10.1080/01495739708936692.
The deterioration of cancellous bone structure due to aging and disease is characterized by a conversion from plate elements to rod elements. Consequently the terms "rod-like" and "plate-like" are frequently used for a subjective classification of cancellous bone. In this work a new morphometric parameter called Structure Model Index (SMI) is introduced, which makes it possible to quantify the characteristic form of a three-dimensionally described structure in terms of the amount of plates and rod composing the structure. The SMI is calculated by means of three-dimensional image analysis based on a differential analysis of the triangulated bone surface. For an ideal plate and rod structure the SMI value is 0 and 3, respectively, independent of the physical dimensions. For a structure with both plates and rods of equal thickness the value lies between 0 and 3, depending on the volume ratio of rods and plates. The SMI parameter is evaluated by examining bone biopsies from different skeletal sites. The bone samples were measured three-dimensionally with a micro-CT system. Samples with the same volume density but varying trabecular architecture can uniquely be characterized with the SMI. Furthermore the SMI values were found to correspond well with the perceived structure type.
由于衰老和疾病导致的松质骨结构退化，其特征是从板状结构单元向杆状结构单元转变。因此，“杆状”和“板状”这两个术语经常用于对松质骨进行主观分类。在这项工作中，引入了一个新的形态计量学参数，称为结构模型指数（SMI），它能够根据构成结构的板和杆的数量，对三维描述结构的特征形式进行量化。SMI是通过基于三角化骨表面的微分分析的三维图像分析来计算的。对于理想的板状和杆状结构，SMI值分别为0和3，与物理尺寸无关。对于具有相同厚度的板和杆的结构，该值介于0和3之间，具体取决于杆和板的体积比。通过检查来自不同骨骼部位的骨活检样本对SMI参数进行评估。使用微型CT系统对骨样本进行三维测量。具有相同体积密度但小梁结构不同的样本可以用SMI进行唯一表征。此外，发现SMI值与所感知的结构类型非常吻合。
