计算机X线摄影与屏-片成像系统的ROC曲线特性比较研究  

A comparison between computed radiography and screen-film in receiver operating characteristic curve

作　　者：王健[1] 王昌元[1] 于凤珍[2] 谢晋东[1] 于兹喜[1] 宋少娟[2] 袁聿德[1] 

机构地区：[1]山东泰山医学院放射系,泰安271000 [2]山东省医学影像研究所

出　　处：《中华放射学杂志》2004年第9期982-987,共6页Chinese Journal of Radiology

摘　　要：目的　研究计算机X线摄影 (computedradiography ,CR)、屏 片系统的ROC曲线特性并对它们进行比较。方法　在中速屏 片系统特性曲线与CR系统总特性曲线基本一致的前提下 ,获得CR系统和中速屏 片系统ROC实验标准体模影像 ,然后变化后处理参数旋转量 (GA)、密度变换(GS)、频率增强 (RN)和频率等级 (RE) ,分别获得CR系统照片。请临床医师用 5值判别法识别所有影像信号 ,并对结果进行ROC解析。结果　 (1)获得CR系统和中速屏 片系统影像的ROC曲线下面积 (Az)分别为 0 875 5 6和 0 9395 8,屏 片系统明显优于CR系统 (t =2 5 2 6 ,P =0 0 35 5 )。 (2 )层次调节结果 :①其他参数不变 ,调节GA =0 6、1 0、2 0、3 0、4 0时 ,CR系统影像的ROC曲线下Az分别为 0 80 0 2 4、0 875 5 6、0 88184、0 8892 8和 0 85 94 4 ,调节GA ,CR系统的ROC曲线下Az有所变换 ,但并不能达到或接近中速屏片系统。②其他参数不变 ,调节GS =0 3、0 4、0 5、0 6、0 7、0 8时 ,CR系统影像的ROC曲线下Az分别为 0 772 5 4、0 875 5 6、0 92 72 0、0 9335 6、0 94 2 6 6和 0 93512 ,调节GS ,CR系统的ROC曲线下Az变换明显 ,可以达到或超过中速屏 片系统。 (3)空间频率调节结果 :①其他参数不变 ,调节RE =0 5、5 0。Objective To study and compare the characteristics of computed radiography (CR) system and screen-film system with receiver operating characteristic (ROC) curve. Methods When H-D curves were identical basically, the images of standard phantom TRG of CR and Middle Speed Screen-Film (MSS/F) system were acquired. Then the value of one of the four post-processing parameters-GA, GS, RN and RE were changed alone, and the images of CR were acquired under each value of the four parameters. All the images were read by five radiologists using the 5-scale method, and the reading data were further analyzed using ROC method. Results (1) The values of Az (the area under ROC curve) of CR and MSS/F systems were 0.875 56 and 0.939 58, MSS/F system was better than CR system (t=2.526,(P=0.0355).) (2)The results of gradation processing: ①The area under the ROC curves of CR were (0.800 24,) 0.875 56, 0.881 84, 0.889 28, and 0.859 44, respectively, as GA=0.6, 1.0, 2.0, 3.0, and 4.0. The area under ROC curves of CR were different but remained lower than that of MSS/F system. ②The area under the ROC curves of CR were 0.772 54, 0.875 56, 0.927 20, 0.933 56, 0.942 66, and 0.935 12, respectively, as GS=0.3, 0.4, 0.5, 0.6, 0.7, and 0.8. The values of Az of CR changed evidently, and some of the values were higher than that of MSS/F system. (3) The results of frequency processing: ①The area under the ROC curves of CR were 0.875 56, 0.925 24, 0.940 84, and 0.941 48, respectively, as RE=0.5, 5.0, 10.0, and 15.0. ②Under the condition of RE=10, the values of Az of the ROC curves of CR were 0.914 38, 0.940 84, 0.895 18, and 0.860 30, respectively, as RN=0, 3, 5, and 8. When the frequency parameter was adjusted, the area under ROC curve of CR system was higher than that of MSS/F system. Conclusions (1) When H-D curves are identical basically, the information of CR system is significantly less than that of MSS/F system. (2) When the post processing parameters are properly adjusted, the information of CR system is higher than that of MSS/

关 键 词：CR系统 ROC曲线 调节 计算机X线摄影 RE 影像 GS 中速 成像系统 GA 

分 类 号：R814.41[医药卫生—影像医学与核医学]