Ramírez Juan Fernando, Isaza Jésica Andrea, Mariaka Isabela, Vélez Jaime Andrés
National University of Colombia, Medellín, Colombia.
Prosthet Orthot Int. 2011 Dec;35(4):459-66. doi: 10.1177/0309364611420478. Epub 2011 Oct 17.
There is a relation between Hounsfield units obtained from computed tomography (CT) scans and bone density. The density of the bones can be used to establish its mechanical properties and therefore to assess the bone mechanical condition using CT images.
To identify the effect of the transfemoral amputation and the use of external lower limb prosthesis in the bone properties, by comparing Young's modulus.
Young's modulus comparison.
Comparison of bone density between the healthy femur and the amputated bone of 20 unilateral transfemoral amputees was done by generating three histograms of the Hounsfield units at different parts of the femur. The histograms were created based on images obtained by CT and the Hounsfield units were translated to Young's modulus to establish the comparison.
The results show a significant difference (p-value <0.05) between the mean value of Young's modulus of healthy and amputated bone.
There is clearly a direct association between the use of external prosthesis and the bone demineralization due the stress shielding phenomenon. The Young's modulus comparison using information from CT images can be a suitable tool to analyze the bone demineralization due to the use of exoprosthesis.
计算机断层扫描（CT）获得的亨氏单位与骨密度之间存在关联。骨密度可用于确定其力学性能，从而利用CT图像评估骨力学状况。
通过比较杨氏模量，确定经股骨截肢及使用下肢外部假体对骨特性的影响。
杨氏模量比较。
通过生成股骨不同部位亨氏单位的三个直方图，对20名单侧经股骨截肢者的健康股骨和截肢骨的骨密度进行比较。直方图基于CT获得的图像创建，亨氏单位转换为杨氏模量以进行比较。
结果显示健康骨和截肢骨的杨氏模量平均值之间存在显著差异（p值<0.05）。
显然，由于应力遮挡现象，外部假体的使用与骨质流失之间存在直接关联。利用CT图像信息进行杨氏模量比较可能是分析因使用外部假体导致骨质流失的合适工具。
