320排螺旋CT单次心动周期手动触发双低剂量CTCA的可行性研究

目的:通过改良320排CT单次心动周期冠状动脉造影扫描技术与对比剂注射技术，以降低辐射剂量与对比剂剂量，并评价技术可行性。方法:前瞻性选取2017年10月至2018年1月之间拟行CTCA扫描的低心率、标准体型患者51例。所选患者随机分为A和B两组。A和B两组管电压分别设置为80 kV和100 kV，均依据体质量指数设置管电流300~500 mA。两组依体质量注射速率分别采用5.0~7.0 mL/s和3.5~5.5 mL/s；对比剂剂量分别采用20~30 mL和35~55 mL。A组采用实时手动触发，B组采用追踪自动触发。评价并比较两组对比剂剂量、辐射剂量与图像质量。结果:A、B两组对比剂剂量差异具有统计学意义，A组对比剂剂量仅28.20±6.44 mL，较B组45.58±6.05 mL降低约30%（t=-9.935，P=0.000）。A组较B组降低约45%的辐射剂量（0.96 mSv±0.27 mSv vs 1.76 mSv±0.28 mSv，t=-10.412，P=0.000）。A组平均评分3.59±0.58，B组平均评分3.66±0.53，Z=-1.618，P=0.106，差异无统计学意义。A组CNR较B组降低13%（20.26±7.34 vs 23.29±7.06，t=-3.350，P=0.001）。结论:低剂量方案可以大幅度减低对比剂剂量与辐射剂量，而图像质量可评估性无明显影响。 

320-detector Row CT Double Low-dose CTCA with Manual Bolus Tracking: A Feasible Study

Objective: To evaluate the value of double low-dose CT coronary angiography (CTCA) by single cardiac cycle acquisition with 320-detector row CT. Methods: 51 patients with low heart rate and normal body type enrolled this study from October 2017 to January 2018. All patients were divided into two groups (Group A and Group B). Group A included 25 patients with tube voltage 80 kV and tube current tailored to body mass index (BMI) (300-500 mA), the injection rate and volume of contrast agent (20-30 mL) tailored to body mass (BM). Group B included 26 patients with tube voltage 100 kV and tube current tailored to BMI (300-500 mA), the injection rate and volume of contrast agent (35-45 mL) tailored to BM. Two groups were evaluated by contrast agent, radiation dose and image quality. P values below 0.05 were considered to be statistically significant. Results: All patients successfully underwent single cardiac cycle CTCA. The mean contrast agent for group A was 28.20 mL; this represents a 30% reduction as compared with that group B (mean, 45.58 mL; t=-9.935, P<0.001). The mean effective dose for group A was 0.96 mSv; this represents a 45% reduction as compared with that group B (mean, 1.76 mSv; t=-10.412, P<0.001). The mean image quality score was 3.59±0.58 obtained with Group A versus 3.66±0.53 obtained with Group B (Z=-1.618, P=0.106). The mean CNR was 20.26±7.34 obtained with Group A versus 23.29±7.06 obtained with Group B (t=-3.350, P=0.001). Conclusion: Double low dose CTCA may decrease the contrast agent and radiation dose keeping image quality assessable in specify patients.