64排螺旋CT冠状动脉成像不同剂量对比分析与低剂量探讨

目的:探讨64排螺旋CT冠状动脉成像低剂量扫描最有效的方法。方法:对心率<70次/min且心率波动<5次/min的受检者,使用前瞻性心电门控;对心律不齐或心率>70次/min的受检者,采用回顾性心电门控,并按患者的体重指数(BMI,kg/m2)应用不同的管电压。分析前瞻性心电门控扫描和根据受检者BMI指数回顾性心电门控扫描两种方式的图像质量和患者的辐射剂量。以常规回顾性心电门控辐射剂量作为对照进行比较。结果:23例采用前瞻性心电门控扫描;55例根据受检者BMI指数,变动管电压的回顾性心电门控扫描。应用前瞻性心电门控比应用常规回顾性门控CT冠状动脉成像的辐射剂量降低70%左右,差异有统计学意义(P<0.05)。回顾性心电门控:BMI<18kg/m2者,管电压用80kV比用120kV辐射剂量降幅亦55%左右;BMI 18～24kg/m2者,管电压用100kV比用120kV辐射剂量降幅25%左右。结论:根据患者的心率、心律、BMI等参数制定合适的扫描方案,就能在获得高质量冠状动脉图像的同时,使患者的辐射剂量降到最低限度。

Coronary artery image comparison of two does of 64-multidetector spiral CT

Objective: To explore a maximum method for producing great 64-multidetector spiral CT images with low does agent.Methods: For patients with heart rate<70 times/ min and the heart rate motion<5 times/ min,prospective electrocardiographically-gated method were applied(group A,23 cases);while for those with heart rate>70 times/ min retrospective electrocardiographically-gated method was applied,voltage was chosen according to the patients' BMI(kg /m2)(group B,55 cases).Image quality and the quantity of radiation of the two groups were compared,routine electrocardiographically-gated radiation quantity were used as reference.Results: Comparing with the reference data,radiation quantity of group A decreased by about 70%,showing significant difference,In group B,for those with BMI<18 kg/m2(80 kV voltage were used) the radiation quantity decreased by 55% comparing with those used 120 kV voltage,for those with BMI 18~24 kg/m2,who used 100 kV voltage showed 25% lower radiation quantity.Conclusion: Choose scan method according to patients' heart rate,heart rhythm and BMI index can get high quality images,and decrease radiation quantity to be minimum at the same time.