64层CT回顾性心电门控下低管电压支气管动脉CTA的可行性研究

Feasibility Study of 64-Slice CT for Bronchial Artery CTA Under Retrospective ECG Gating and Low Voltage

目的探讨64层CT在回顾性心电门控下以低管电压行支气管动脉CT血管造影(CTA)的可行性。方法采用前瞻性研究,将临床需要行支气管动脉CTA检查的80例患者随机分为对照组和观察组各40例,采用64层CT进行支气管动脉CTA。对照组管电压为120 kVp,观察组在回顾性心电门控下检查,管电压为80 kVp。比较2组图像对纵隔段支气管动脉的显示率、主观质量、客观质量(包括主动脉CT值、图像背景噪声、信噪比、对比噪声比)、辐射剂量(包括平均CT剂量指数、剂量长度乘积、有效剂量)的差异。结果80例中顺利完成检查77例(对照组和观察组分别38例和39例)。2组纵隔段支气管动脉的显示率无差异(P>0.05);观察组主动脉CT值、图像背景噪声、信噪比、对比噪声比均高于对照组(P均<0.05);主观质量中图像优良率高于对照组(P<0.05),合格率与对照组无差异(P>0.05);观察组辐射剂量(包括平均CT剂量指数、剂量长度乘积、有效剂量)低于对照组(P均<0.05)。结论64层CT在回顾性心电门控下以低管电压行支气管动脉CTA是可行性的,可获得满意的图像质量,并明显降低辐射剂量。

Objective To investigate the feasibility of 64-slice CT in the bronchial artery CTA with low tube voltage under retrospective ECG. Methods A prospective study was conducted in which 80 patients with clinically required bronchial artery CTA were randomly assigned to a control group and an observation group of 40 patients. 64-slice CT was used for bronchial artery CTA. The control group tube voltage was 120 kVp,and the experimental group was examined under retrospective ECG gating. The tube voltage was 80 kVp. Compare the display rate,subjective quality,objective quality(including aortic CT value,image background noise,signal-to-noise ratio,contrast-to-noise ratio) and radiation dose(including average CT dose index,dose) of the bronchial artery in the mediastinal segment of the two groups of images and difference in dose-length product and effective dose. Results Of the 80 cases,78 cases were successfully completed(38 cases and 39 cases in the control group and the observation group,respectively). There was no difference in the display rate of bronchial artery between the two groups(P>0.05). The aortic CT value,image background noise,signal-to-noise ratio and contrast-to-noise ratio of the observation group were higher than those of the control group(P<0.05);subjective quality. The excellent rate of image was higher than that of the control group(P<0.05),and the pass rate was not different from that of the control group(P>0.05). The radiation dose(including the average CT dose index,dose length product,effective dose) of the observation group was lower than that of the control group(P>0.05). Conclusion 64-slice CT is feasible to perform bronchial artery CTA with low tube voltage under retrospective ECG gating. A satisfactory image quality can be obtained and the radiation dose can be significantly reduced.