胸部双能减影与常规数字X线摄影对信号检出效能的比较

目的比较双能减影(DES)与常规数字X线摄影(CDR)对信号的检出效能。方法将200个直径为4mm塑料小球作为信号分别置于塑料板和健康志愿者右胸上部摄取CDR和DES片。由3位放射科医师用5等级判别法各自独立阅片,用ROCkit软件对观察结果进行ROC曲线分析。结果当信号置于塑料板上时,CDR和DES的Az值分别为0.9931和0.9879,P值为0.4851(双尾)>0.05,差异无统计学意义。当信号置于右胸上部时,CDR和DES的Az值分别为0.7276和0.8561,P值为0.0002(双尾)<0.01,差异有统计学意义。结论DES可以去除肋骨对胸部信号的遮挡,使DES对胸部信号的检出能力明显高于CDR,提示DES在胸部的应用具有良好的前景。

Comparative experimental study of dual energy subtraction and conventional digital radiography on chest

Objective To compare the efficiency of dual energy subtraction and conventional direct digital radiography in signal detecting ability. Methods 200 plastic balls which were 4 mm in diameter were taken as signals and were placed on a 10 cm thick plastic board and the right upper thorax of a healthy volunteer. The signals were examined by DES and CDR separately and were estimated by 3 radiologists with 5-value-differentiation method. ROC curve analysis was made by ROC kit software. Results when signals on plastic board were detected by CDR and DES , ROC curve analysis indicated that there was no significant difference (P=0.4851>0.05,two-tailed) between the area under the ROC curves of the two methods (Az= 0.9931 for CDR and Az=0.9879 for DES). The difference was significant (P=0.0002<0.01 ,two-tailed) between the area under the ROC curves of CDR and DES (Az=0.7276 for CDR and Az=0.8561 for DES), when the signals on the right upper thorax of a volunteer were detected by the two methods. Conclusion DES surpasses CDR in detecting signals on thorax without superposition of ribs. There is good outlook in the application of DES in thorax examination.