目的:探讨双源CT(DSCT)低管电压结合不同管电流在冠状动脉CT血管成像(CTCA)中的应用.方法:回顾性分析168例行DSCT检查冠状动脉的受检者CTCA图像资料,按照X射线管的管电流和重建技术,根据X射线管A管不同管电流将受检者分为4组,180 mAs组(37例)、150 mAs组(39例)、120 mAs组(44例)和90 mAs组(48例).比较4组受检者平均CT值、图像噪声、信号噪声比(SNR)、对比噪声比(CNR)和图像质量主观评分,以及容积CT剂量指数(CTDIvol)、剂量长度乘积(DLP)和有效辐射剂量(ERD).结果:4组受检者冠状动脉段数显示率基本一致,且图像质量评分和平均CT值差异无统计学意义(x2=1.371,P＞0.05);但4组受检者图像质量平均分值、图像噪声、SNR、CNR、CTDIvol、DLP和ERD比较,差异有统计学意义(F=2.772,F=4.374,F=4.151,F=4.007,F=28.746,F=19.835,F=41.126;P＜0.05);180 mAs组和90 mAs组受检者图像质量优于150 mAs组和120 mAs组;90 mAs组图像SD高于150 mAs组和120 mAs组,90 mAs组图像SNR和CNR低于150 mAs组和120 mAs组,差异有统计学意义(t=2.238,t=2.353;t=2.652,t=2.703;t=2.425,t=2.498;P＜0.05);90 mAs组受检者的CTDIvol、DLP及ERD均低于其他3组,差异有统计学意义(t=4.998,t=3.716,t=5.002;t=4.673,t=2.999,t=3.876;t=2.811,t=2.064,t=3.141;P＜0.05).结论:双源CT低管电压结合90 mAs低管电流既可获得高质量图像,又可以降低辐射剂量.%Objective: To discuss the application of dual source CT(DSCT) low tube voltage combined with different tube currents in computed tomography coronary angiography (CTCA). Methods: The CTCA images of 168 patients who received the examination of DSCT for coronary artery were researched by using retrospective analysis. According to the tube current and reconstruction technique of X-ray, and depending on the different tube current of X-ray tube, the subjects were divided into 4 groups which included 180mAs group (37 cases), 150 mAs group (39 cases), 120 mAs group (44 cases) and 90 mAs (48 cases). The average CT value, image noise, signal noise ratio(SNR), contrast noise ratio(CNR), subjective scores of image quality, the volume CT dose index(CTDIvol), the dose length product(DLP) and the effective radiation dose(ERD) among the four groups were compared. Results: The display rates of coronary artery segments of the 4 groups were basically coincident, and the differences of quality score of image and average CT value among the 4 groups were not statistically significant(x2=1.371, P>0.05). While the differences of average score of image quality, image noise, SNR, CNR, CTDIvol, DLP and ERD among 4 groups were significant (F=2.772, F=4.374, F=4.151, F=4.007, F=28.746, F=19.835, F=41.126, P<0.05), respectively. And the image quality of 180mAs group and 90mAs group were significantly better than that of 150mAs and 120mAs, and the image SD of 90mAs group was significantly higher than that of 150mAs group and 120mAs group, and the SNR and CNR of 90 mAs group were significantly lower than that of 150mAs group and 120mAs group (t=2.238, t=2.353. t=2.652, t=2.703. t=2.425, t=2.498. P<0.05). Besides, the CTDIvol, DLP and ERD of 90 mAs group were significantly lower than that of other three groups (t=4.998, t=3.716, t=5.002; t=4.673, t=2.999, t=3.876; t=2.811, t=2.064, t=3.141; P<0.05), respectively. Conclusion: DSCT low tube voltage combined with 90 mAs low tube current not only can obtain high-quality images, but also can reduce the radiation dose.
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