Wackers F J, Bodenheimer M, Fleiss J L, Brown M
Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut 06510.
J Am Coll Cardiol. 1993 Apr;21(5):1064-74. doi: 10.1016/0735-1097(93)90226-q.
This study was designed to assess factors affecting interobserver agreement in interpretation of planar thallium-201 stress imaging in the Multicenter Study on Silent Myocardial Ischemia (MSSMI).
Five hundred fifty-six planar thallium-201 images were interpreted in 24 clinical centers and in a Radionuclide Core Laboratory. The trial's Coordinating and Data Center observed that the participating clinical centers interpreted a significantly greater number of thallium-201 stress studies as abnormal (i.e., myocardial ischemia or scar) than the Core Laboratory, and overall agreement was poor (kappa 0.27).
Agreement in image interpretation between clinical centers and the Radionuclide Core Laboratory was analyzed by kappa statistics. The reproducibility of the Core Laboratory results on 41 randomly selected test studies was excellent (kappa 0.77). In contrast, the reproducibility of interpretation in the clinical centers on their own studies was at best fair (kappa 0.45). It was hypothesized that the poor agreement and reproducibility in the clinical centers were caused by lack of standardization of image display and lack of objective criteria for image interpretation. To test the effect of standardization, 13 clinical investigators interpreted the same 41 test studies using 1) uniform image display, and 2) uniform quantification of images.
The agreement in interpretation between clinical investigators and the Radionuclide Core Laboratory improved modestly with uniformity of image display (kappa 0.57) but improved markedly (kappa 0.66) with quantitative circumferential profile analysis.
Lack of standardization in image display and lack of objective criteria for interpretation of thallium-201 images are responsible for suboptimal reproducibility and poor interlaboratory agreement in the interpretation of thallium-201 stress imaging. The adoption of a uniformly accepted method for computer quantification of myocardial perfusion images is crucial to improve agreement in interpretation.
本研究旨在评估在无症状心肌缺血多中心研究（MSSMI）中，影响平面铊-201负荷显像观察者间一致性的因素。
24个临床中心和一个放射性核素核心实验室对556幅平面铊-201图像进行了解读。试验的协调和数据中心观察到，参与的临床中心将显著更多的铊-201负荷研究解读为异常（即心肌缺血或瘢痕），而核心实验室的解读结果则不同，总体一致性较差（kappa值为0.27）。
采用kappa统计分析临床中心与放射性核素核心实验室在图像解读方面的一致性。核心实验室对41项随机选择的测试研究结果的可重复性极佳（kappa值为0.77）。相比之下，临床中心对自身研究解读的可重复性充其量只是一般（kappa值为0.45）。据推测，临床中心一致性和可重复性较差是由于图像显示缺乏标准化以及图像解读缺乏客观标准所致。为了测试标准化的效果，13名临床研究人员对相同的41项测试研究进行了解读，采用了：1）统一的图像显示；2）图像的统一量化。
随着图像显示的一致性提高，临床研究人员与放射性核素核心实验室之间的解读一致性略有改善（kappa值为0.57），但通过定量圆周轮廓分析显著改善（kappa值为0.66）。
图像显示缺乏标准化以及铊-201图像解读缺乏客观标准，是铊-201负荷显像解读中可重复性欠佳和实验室间一致性较差的原因。采用一种统一认可的心肌灌注图像计算机量化方法对于提高解读一致性至关重要。
