优化对比剂注射时间在减少颈部CTA对比剂硬化伪影中的应用

Application of optimizing injection time of contrast agent in reducing contrast hardening artifacts in CTA of neck

目的:探讨通过采用不同的对比剂注射时间减轻对锁骨下静脉处对比剂硬化伪影,提高颈部CTA图像质量的可行性。方法:选取2019年9月—12月来南京大学医学院附属鼓楼医院行颈部CTA检查的患者240例,采用随机数字表法分为A~F共6组,每组40例。A~F组对比剂注射时间分别为15 s、13 s、12 s、11 s、10 s和9 s,注射速率均为4.5 mL/s,对比剂注射结束后立即以4.0 mL/s跟注0.9%氯化钠溶液30 m L。各组采用的扫描参数及重建方法均完全一致。比较各组图像质量和伪影评价。结果:由F~A组,随着对比剂注射时间和总量的增加,颈总动脉血管CT值略有升高,但各组间无统计学差异。硬化伪影评价指标△CT值和BHA也逐渐升高,伪影逐渐加重,P均<0.05,差异具有统计学意义。图像质量的主观评分呈下降趋势,当注射时间为15 s时,即A组有3例患者图像局部伪影较重,影响诊断,主观评分2分。B~F组所有图像评分均≥3分,满足诊断要求,但E、F两组图像质量评分优于A、B、C、D四组,差异有统计学意义(P<0.05),而E、F两组间图像质量无统计学差异(P>0.05)。结论:使用64排CT进行颈部CTA检查,对比剂注射时间为9 s并跟注一定量的0.9%氯化钠溶液冲洗,锁骨下静脉处对比剂硬化伪影最小,对比剂用量最少,图像质量评分最高,可作为临床常规应用。

Objective To investigate the feasibility of reducing contrast hardening artifacts in subclavian vein and improving the image quality of cervical CTA by using different injection time of contrast agent.Methods 240 patients with cervical CTA in Nanjing Drum Tower Hospital,the Affiliated Hospital of Nanjing University Medical School from September to December 2019 were prospectively collected and randomly divided into 6 groups(A to F,40 cases in each group).The injection time was 15 s,13 s,12 s,11 s,10 s and 9 s in group A to F,and the injection rate was 4.5 mL/s.After the injection,30 mL of 0.9%sodium chloride solution was injected immediately with 4.0 mL/s.The scanning parameters and reconstruction methods used in each group were completely consistent,comparing image quality and artifact evaluation across groups.Results In group F to A,with the increase of injection time and total amount of contrast medium,the CT value of common carotid artery increased slightly,but there was no significant difference among the groups.The values of△CT and BHA were also gradually increased,and the artifacts were gradually aggravated(P<0.05).The subjective score of image quality showed a downward trend.When the injection time was 15 s,there were 3 patients in group A with severe local image artifacts,which affected the diagnosis.The subjective score was 2 points.All the image scores of group B to F were more than or equal to 3 points,which met the diagnostic requirements,but the image quality scores of group E and F were better than those of group A,B,C and D(P<0.05),while there was no significant difference in image quality between group e and F.Conclusion Using 64 slice CT for neck CTA examination,the injection time of contrast agent is 9 s,followed by a certain amount of 0.9%sodium chloride solution irrigation,the contrast agent hardening artifact in subclavian vein is the smallest,the dosage of contrast agent is the least,and the image quality score is the highest,which can be used as a routine clinical application.