放大率校正方法在人工髋关节置换术前X线摄片上的改良及其可行性评估  

Modification and valuation of revise of magnification for radiograph during preoperative planning of total hip arthroplasty

作　　者：许杰[1] 马若凡[1] 丁悦[1] 刘尚礼[1] 

机构地区：[1]中山大学附属第二医院骨外科,广州510120

出　　处：《中国医师进修杂志（外科版）》2008年第3期14-17,共4页Chinese Journal of Postgraduates of Medicine

基　　金：广东省科技计划项目（2006B12901002）

摘　　要：目的探讨改良人工髋关节置换术前X线摄片放大率的校正方法在满足基于X线摄片术前模板精确测量方面的应用价值。方法随机选取2006年1月至2007年1月行人工髋关节置换术后骨盆正位X线摄片的100例患者，采用改良Conn的方法，将放大率参照物由股骨同一水平高度移至患髋侧X线暗盒上。同时记录病例的体形因素，以修正其对参照物的放大率变异的影响。随机选取50例骨盆CT片，测量其股骨到检查床的投射距离，以进一步明确体形因素对放大率的影响。结果X线及CT资料均显示病例体形因素变化对投射距离及影像放大率的变化影响较小。根据参照物作放大率校正后，对于小尺寸区间（28～44mm）及中等尺寸区间（〉44mm且≤54mm）的测量值与真实值偏差分别为（0．3006±0．2360）mm、（0．7460±0．5433）mm，大尺寸区间（〉54mm）则偏差较大，为（1．3998±1．0408）mm。应用Levene检验，显示变异程度不等（P〈0．05）。结论虽然改良法中测量值与真实值间仍存在偏差，而且随着测量长度的增加，偏差越发严重，但对于通常尺寸假体的测量，测量值与真实值的吻合程度较高，可满足大多数患者术前计划中假体尺寸的选择。在实际应用比较中，改良法中参照物的置放更为便捷。Objective To modify the method for revising magnification for radiograph and investigate its practicability in increasing the accuracy of choice of component during preoperative planning. Methods One hundred post-operatlve radiographs of those who preformed total hip arthroplasty taken from January 2006 to January 2007 were picked out randomly. Conn method placing a marker of known diameter beside the interest thigh on the same level of the femur was modified, and the marker was placed on the oper- ative side plate during X-ray exam. Meanwhile index of bedy shape was recorded tO be evaluated its influence for magnification. Results The variation of magnification was small and limited among the cases with different index of body shape. Absolute error of measurement ranged from 28 mm to 44 mm,more than 44 nun and no more than 54 mm were （0.3006± 0.2360） mm and（0.7460 ± 0.5433） nun respectively. But the absolute error of measurement more than 54 nun was （ 1.3998 ± 1.0408 ） nun and unacceptable for preoperative planning. Furthermore, in order to confirm the confidence of the modified method, the CT scans of another 50 patients were picked out randomly, and showed the distance between the rotation center of hip and the table, which was an acknowledged influencing factor of magnification of radiograph, was changed little responding to body shape. Conclusions Variant magnification was caused by variant distance between the rotation center of hip and the table. Little change of the distance for the patients with different body shape leaded to feasibility of the modified method for not-large--size measurement, which was easier and more friendly.

关 键 词：关节成形术 置换 髋 X线摄影放大 

分 类 号：R687.4[医药卫生—骨科学] R816.8[医药卫生—外科学]