Abstract:

        Objective  To explore a method for measuring bone density base on three- dimensional reconstruction and finite element analysis.  Methods  One spine specimen (C3~L5) were used for this experiment. It was treated with thin-slice high resolution CT scan and three-dimensional reconstruction in Mimics, volume meshing in Ansys, assigned with 10 and 400 kinds of material attributes Mimics, then exported to Ansys to calculate the volumes of the block elements of every type of material attributes. The mass and the density of the specimen could be harvested according to the empirical formula concerning the gray value and the bone mineral density. The mass of control group (C3~L5) was measured with an electronic balance. All results were statistically treated with one-way ANOVA.  Results   The apparent densities of C3~L5 of control group, group of 10 and 400 kinds of material attributes were 0.62±0.09, 0.5813±0.0806 and 0.5813±0.0805 g/cm3 respectively. P value was more than 0.1 when the density of control group compared with that of experimental groups which were assigned with 10 and 400 kinds of material attributes, while it was 0.997 within experimental groups. Conclusions   Firstly, this method was able to measure the mass and the bone density quantitatively, as well as that of compact bone and cancellated bone; Secondly, to assign 10 kinds of material attributes to three-dimensional model of spine could match the needs for measurements; Thirdly, our experience could be used as an initial preparation for the unification of bone mineral density and finite element analysis.

Key words: Bone apparent density, Spine, Three-dimensional reconstruction, Finite element, Osteoporosis