不同CT剂量肺结节检出率的体模研究

Detectability of lung nodules in different dose CT in phantom study

目的比较不同CT扫描协议对胸部体模中模拟肺结节的检出率。方法应用5种扫描方案使用不同CT扫描剂量分别对胸部体模进行扫描,四位胸部放射科医师分析CT图像,同时记录检测的磨玻璃肺结节,并进行统计学分析。记录不同扫描序列的辐射剂量。结果各低剂量组间肺结节检出率比较差异无统计学意义(P>0.05),低剂量组均显著低于常规剂量组的肺结节检出率(P<0.001)。CT值为-630和-800 Hu的磨玻璃肺结节检出率各低剂量组均显著低于常规剂量组(P<0.01)。不同观察者具有较好的一致性(κ值>0.41)。等效扫描剂量为0.53~4.24 mSv。结论低剂量CT(ED=0.53~1.05 mSv)扫描对于肺结节的检出率无差异,但均显著低于常规剂量,进行胸部筛查时应考虑到这种差异,从而选择更合适的扫描方案。

Objective To compare the detectability of different dose computed tomography(CT)protocols on the detection of lung nodules in phantom study.Methods A chest phantom was scanned by five different doses schemes.The CT images were analyzed by Four chest radiologists.Pulmonary ground-glass nodules were assessed by statistical analysis,the radiation dose of different scan sequences was recorded.Results There were no significant differences in the detectability of lung nodules among different LD dose groups(P>0.05).And the detectability of lung nodules in low-dose group were significantly lower than those in conventional dose group(P<0.001).Moreover the detectability of pulmonary ground-glass nodules in low-dose group with CT value being-630Hu and-800Hu were significantly lower than those in conventional dose group(P<0.01).There existed better consistency among different observers(κ-value>0.41),and equivalent dose values ranged from 0.53mSv to 4.24mSv.Conclusion There is no significant difference in detectability of lung nodules between different low-dose CT scanning(ED=0.53~1.05mSv),however,which is significantly lower than that conventional dose scanning,therefor,it should be paid much attention to the difference farther.