采用对比剂团注追踪技术进行头颅CTA时的监测扫描启动时间研究

Study on starting time of monitoring scan in head CTA with contrast agent bolus tracking technique

目的:探讨采用对比剂团注追踪技术进行头颅CT血管成像(CT angiography,CTA)时的最佳监测扫描启动时间。方法:前瞻性收集某院行头颅CTA检查的患者400例,按预约先后顺序分为A、B 2组,前200例为A组,后200例为B组。A组在对比剂注射后8 s开始启动监测扫描。记录监测扫描的触发时间、触发时CT值、曝光次数和辐射剂量;测量双侧颈内动脉末段的CT值,取二者平均值作为颈内动脉CT值,并由2名放射诊断医师对图像质量进行主观评价。B组监测扫描的启动时间为12 s,其余参数、测量评价方法与A组一致。比较2组患者监测扫描的曝光次数、触发时间、触发CT值、颈内动脉CT值、剂量长度乘积(dose length product,DLP)、图像质量评分和触发时间分布。应用SPSS 20.0软件进行统计学分析。结果:2组患者不同触发时间病例分布无统计学差异(P>0.05),监测扫描的触发时间、触发CT值、颈内动脉CT值和图像质量评分均无统计学差异(P均>0.05)。B组比A组的监测曝光次数、DLP分别减少了45.2%、45.1%,差异具有统计学意义(P均<0.05)。结论:采用团注追踪技术进行头颅CTA扫描,监测扫描的启动时间设置为12 s时,可以在保证图像质量的前提下,减少患者的辐射剂量。

Objective To investigate the optimal starting time of monitoring scan for head CT angiography(CT angiography,CTA)using contrast agent bolus tracking technique.Methods A prospective collection of 400 patients who underwent head CTA were divided into group A(the first 200 cases)and group B(the last 200 cases)according to the order of appointment.In group A the monitoring scan was started 8 s after contrast injection;the trigger time,CT value,times of exposures and radiation dose of the monitoring scan were recorded;the CT values of the end segments of the internal carotid arteries were measured bilaterally,and the average value of the two ones was taken as the CT value of the internal carotid arteries,and the image quality was subjectively evaluated by two diagnostic radiologists.In group B the monitoring scan was started 12 s after contrast injection,and the rest of the parameters and measurement and evaluation methods were the same as those in group A;the times of exposures,trigger time,trigger CT value,internal carotid CT value,dose length product(DLP),image quality score and trigger time distribution were compared between the two groups.SPSS 20.0 software was used for statistical analysis.Results The two groups had no any statistical differences in the distribution of cases with different trigger time and in the trigger time,trigger CT value,internal carotid artery CT value and image quality score of the monitoring scan(all P>0.05).Group B had lower values than group A in exposure times and DLP by 45.2%and 45.1%,respectively,with statistically significant differences(all P<0.05).Conclusion Head CTA using contrast agent bolus tracking technique can reduce the radiation dose to the patient while ensuring image quality when the starting time of the monitored scan is set to 12 s after injection.[Chinese Medical Equipment Journal,2022,43(3):66-69]