双源CT半自动模式联合高级模型迭代重建在低剂量胸部CT中的应用

Application of dual-source CT semi-automatic mode combined with ADMIRE in low-dose thoracic CT

目的探讨双源CT半自动模式联合高级模型迭代重建(ADMIRE)在低剂量胸部CT中的应用。方法选取拟行胸部CT的500例体检者为研究对象。将患者随机分成5组,每组各100例。F组为常规剂量组(管电压120 kV),使用滤波反投影法(FBP)进行重建;A1、A2、B1、B2组为低剂量组(A1、A2组管电压80 kV,B1、B2组管电压70 kV),A1、B1组开启半自动模式(semi),使用ADMIRE 3级进行重建;A2、B2组关闭半自动模式,其余条件同A1、B1组。用主观和客观指标评价常规组与各低剂量组的图像质量。结果A1、B1与F组的信噪比(SNR)优于A2、B2组(P<0.05)。F组与低剂量组在剂量指数(CTDI)、剂量长度乘积(DLP)、有效剂量(ED)上的差异均有统计学意义(P<0.05)。图像质量主观评价F、A1、A2、B1组的差异无统计学意义(P>0.05),B2组最差(P<0.05)。B1、B2组线束硬化伪影较F、A1、A2组严重,差异具有统计学意义(P<0.05)。结论低剂量胸部CT扫描中,半自动模式联合ADMIRE算法可在降低辐射剂量的同时保证图像质量;且相同条件下,80 kV图像较70 kV更具优势。

Objective To explore the application of dual-source CT semi-automatic mode combined with advanced model iterative reconstruction(ADMIRE) in low-dose thoracic CT.Methods A total of 500 patients who were scheduled for chest CT were selected.The patients were randomly divided into five groups(n=100).Group F was a conventional dose group(with a tube voltage of 120 kV),and filtered back projection(FBP) was used for reconstruction.Groups A1,A1,B1 and B2 were low dose groups(with a tube voltage of 80 kV for groups A1 and A2 and a tube voltage of 70 kV for groups Bl and B2).Groups A1 and B1 turned on semi-automatic mode(semi),and ADMIRE(grade 3) was used for reconstruction.Groups A2 and B2 turned off semi-automatic mode,while other conditions were the same as those in groups A1 and B1.The conventional group and each low dose group were evaluated for image quality according to subjective and objective indexes.Results The signal/noise ratios(SNRs) of groups A1,B1 and F were better than those of groups A2 and B2.There were significant differences in CT dose index(CTDI),dose length product(DLP) and effective dose(ED) between group F and the low dose groups(P<0.05).There was no difference in subjective evaluation of image quality in groups F,A1,A2 and B1,but the worst was found in group B2(P<0.05).The artifact scores of harness sclerosis in groups B1 and B2 were lower than those in groups F,A1 and A2(P<0.05).Conclusions In low-dose chest CT scanning,semi-automatic mode combined with ADMIRE algorithm can reduce the radiation dose while ensuring image quality.