取点数目对基于CT导航股骨配准精度影响的研究

Study on the Effect of Different Number of Points Involved to the Accuracy of Femora Registration with Computed Tomography-guided Navigation System

目的:探讨不同取点数目对基于术前CT导航的股骨配准精度的影响,确定临床最少取点数目。方法:在3D打印模型股骨上进行不同取点数目配准试验,通过Matlab软件对点云数据进行处理,再经Geomagic软件进行封装及配准,最后通过SPSS软件对相关参数进行统计学分析。结果:取点数目越多配准精度越高;取绝大部分点时配准精度最高:每片点云取15个点,配准结果满意,此时股骨近端点云集配准误差为(0.509±0.196)mm,股骨远端点云集配准误差为(0.472±0.197)mm:当每片点云取点数目大于等于15时,与取绝大部分点云配准精度间无统计学差异。结论:取点数量越多配准精度越高,结合实际临床情况,每片点云应最少取15个点。

Objective： To analyze the effect of different number of points involved to the accuracy of femora registration with preoperative computed tomography-guided navigation system and ascertain the minimum number of points involved. Methods： Registration experiments based on various number of points involved were performed on three-dimensional printing femoral prosthesis. Matlab was used for point cloud data processing. Data was then imported into Geomagic Studio software to analyze and registrant. Finally, SPSS was applied here to analyze the collected data. Results： The more points involved in the femora registration the higher accuracy we could be achieved, we got the highest accuracy when most points were involved. And when the number of each point cloud was larger or equaled to 15, the registration was fine, in another word, the error of registration of proximal femoral point cloud was limited to （0.509±0.196）mm, besides, the error of registration of distal femoral point cloud was limited to （0.472±0.197） mm. When the number of point cloud was larger or equals to 15, the registration results analysis showed no statistic difference comparing with results when most points involved. Conclusion： The more points involved in registration the higher accuracy could be achieved. Considering clinical practice, the number of points involved of each point cloud should be larger or equals to 15.