Mok James M, Berven Sigurd H, Diab Mohammad, Hackbarth Melissa, Hu Serena S, Deviren Vedat
Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA.
Spine (Phila Pa 1976). 2008 Mar 15;33(6):681-6. doi: 10.1097/BRS.0b013e318166aa8d.
This study is a reliability analysis of coronal Cobb angle measurements in adolescent idiopathic scoliosis obtained by multiple observers.
We sought to quantify and compare the interobserver reliability of conventional radiographs and 3 methods of digital radiography.
The use of digital radiography for the evaluation of adolescent idiopathic scoliosis is being widely adopted. Previous studies comparing manual and computer-based measurements have found excellent intraobserver reliability for both techniques. Interobserver reliability of computer-based measurements on digital radiographs has not been compared with manual measurements on conventional radiographs. Other commonly used forms of output of digital radiography have not been studied.
Preoperative standing posteroanterior full-length spine radiographs from 40 patients with adolescent idiopathic scoliosis were examined by 4 observers. Patients were divided into 2 groups of 20 patients. In 1 group, radiographs were obtained by conventional technique. In the other group, radiographs were obtained using a digital radiography system. Three types of output of the identical image obtained by a digital radiography system were examined, including computer-based image, printing of the image fitted onto a single film, or printing of the image onto 2 unstitched films. The Cobb angle, upper vertebra, and lower vertebra of the major curve were measured by each observer. Interobserver reliability for each technique was calculated by intraclass correlation coefficient and interobserver variance.
Interobserver reliability as described by intraclass correlation coefficient and interobserver variance was excellent (0.93-0.98) for measurements made on conventional, computer-based, and fitted printed radiographs. The intraclass correlation coefficient was good (0.87) in measurements obtained on radiographs printed on 2 unstitched films.
Measurements made on conventional and digital radiographs using manual and computer-based techniques have similar good to excellent interobserver reliability. Interobserver reliability was lower for digital radiographs when printed onto 2 unstitched films. The results suggest that different observers will obtain similar measurements when viewing the same image, but care should be taken when interpreting images printed on 2 unstitched films.
本研究是对多位观察者所获得的青少年特发性脊柱侧凸冠状面Cobb角测量值的可靠性分析。
我们试图量化并比较传统X线片和3种数字X线摄影方法在观察者间的可靠性。
数字X线摄影在青少年特发性脊柱侧凸评估中的应用正在被广泛采用。先前比较手工测量和基于计算机测量的研究发现，这两种技术在观察者内的可靠性都很高。数字X线片上基于计算机测量的观察者间可靠性尚未与传统X线片上的手工测量进行比较。数字X线摄影的其他常用输出形式也未被研究。
4位观察者对40例青少年特发性脊柱侧凸患者的术前站立后前位全长脊柱X线片进行检查。患者被分为两组，每组20例。一组采用传统技术获取X线片，另一组使用数字X线摄影系统获取X线片。对数字X线摄影系统获得的同一图像的三种输出类型进行检查，包括基于计算机的图像、印在单张胶片上的图像或印在两张未拼接胶片上的图像。每位观察者测量主弯的Cobb角、上位椎体和下位椎体。通过组内相关系数和观察者间方差计算每种技术的观察者间可靠性。
对于传统的、基于计算机的和印在单张胶片上的X线片测量，组内相关系数和观察者间方差所描述的观察者间可靠性极佳（0.93 - 0.98）。印在两张未拼接胶片上的X线片测量的组内相关系数良好（0.87）。
使用手工和基于计算机技术对传统X线片和数字X线片进行测量，观察者间可靠性相似，均为良好到极佳。当数字X线片印在两张未拼接胶片上时，观察者间可靠性较低。结果表明，不同观察者在查看同一图像时会获得相似的测量值，但在解读印在两张未拼接胶片上的图像时应谨慎。
