双源CT引导肺穿刺活检低剂量策略的临床应用研究

Clinical research of low-dose protocol for dual-source CT-guided percutaneous pulmonary biopsy

目的探讨低X射线辐射剂量扫描在双源计算机断层扫描(CT)引导肺活检术中的应用,寻求减少剂量的最优方案。方法选择需行肺活检患者70例,35例患者采用双、单源及自动管电流扫描,每例患者获5组图像(A组:100/Sn140 kV,B组:120 kV,C组:100 kV,D组:80 kV,E组:70 kV);35例患者采用双源与不同管电流组合,每例患者获6组图像(F组:100/Sn140 kV-自动管电流,G组:100/Sn140 kV-固定管电流,H组:80/Sn140 kV-自动管电流,I组:80/Sn140 kV-固定管电流,J组:140/80 kV-自动管电流,K组:140/80 kV-固定管电流)。于A~K组图像的冈下肌、穿刺病灶及灶旁肺内取感兴趣区(ROI),计算每组ROI信噪比、病灶与肺的对比噪声比;对每组图像质量主客观评分,记录每组CT剂量指数(CTDI)和剂量长度乘积(DLP),计算有效射线剂量(ED),比较各组图像质量及ED。结果A、D、E组的CTDI、DLP及ED均低于B、C组的(P<0.001);A、B、C、D、E组各ROI的CT差异无统计学意义;D、E组各ROI噪声高于其他3组(P<0.001),A、B、C组噪声差异无统计学意义;D、E组各ROI的信噪比及病灶与肺的对比噪声比均低于其他3组(P<0.001);D、E组各主观评分均低于A、B、C组,A、B、C组各主观评分差异无统计学意义。I组的CTDI、DLP、ED均低于其他5组的(P<0.001);F、G、H、I、J、K组各ROI主、客观指标组间差异均无统计学意义。结论CT引导采用80/Sn140 kV-固定管电流扫描方案,图像质量满足穿刺要求的同时明显降低了ED,适合临床推广。

Objective To investigate the application of low X-ray radiation dose scanning for dual-source computed tomography(CT)-guided percutaneous pulmonary biopsy(PPB),and to seek out the optimal protocol to reduce the radiation dose.Methods Seventy patients requiring CT-guided PPB were selected.35 patients underwent dual-source and single-source scanning,while tube current or automatic tube current were applied to them.Five sets of images were obtained for each patient(Group A:100/Sn140 kV,Group B:120 kV,Group C:100 kV,Group D:80 kV,Group E:70 kV).The combination mode of dual-source and different tube currents was adopted in 35 patients,and six sets of images were obtained for each patient(Group F:100/Sn140 kV-automatic tube current,Group G:100/Sn140 kV-fixed tube current,Group H:80/Sn140 kV-automatic tube current,Group I:80/Sn140 kV-Fixed tube current,Group J:140/80 kV-automatic tube current,and Group K:140/80 kV-fixed tube current).Region of interest(ROI)was obtained from infra-spinatus,puncture lesion and lung tissue adjacent to the lesion in each group of images.Signal-to-noise ratio for each ROI and contrast-to-noise ratio between puncture lesions and surrounding lung tissues were calculat-ed,and the image qualityof each group subjectively and objectively evaluated.The CT dose index(CTDI)and dose-length product(DLP)of each group of images were recorded to calculate the effective radiation dose(ED).The image quality and ED of each group were compared.Results The CTDI,DLP and ED of groups A,D and E were lower than group B and group C(P<0.001).There was no statistical difference for CT-value of each ROI in group A~E.The image noise of group D and group E was significantly higher than the other groups(P<0.001),and there was no statistical difference for image noise between group A~C.The signal-to-noise ratio of each ROI and contrast-to-noise ratio of lesion and lung tissue in group D and group E were significantly lower than the other groups(P<0.001).The subjective scores of group D and group E were both lower than the groups A~C,and there was no significant difference in the subjective scores between groups A~C.The CTDI,DLP and ED of group I were lower than the others five groups(P<0.001).There were no sig-nificant differences in all the objective and the subjective indexes of the group F~K images.Conclusion With CT-guided PPB using 80/Sn140 kV and fixed tube current scanning,the image quality can not only meet the requirements of puncture,but also significantly reduce ED,which is suitable for clinical promotion.