64层头颈联合CTA经左侧上肢注射对比剂的最佳时间探讨

Investigation of the Optimal Injection Time of the Contrast Media in 64 Slice Head-Neck CTA Injected from Left Upper Extremity

目的探讨64层CT在头颈联合动脉成像中选择左侧上肢静脉注射对比剂的最佳时间。方法前瞻性选取行头颈动脉CTA检查的患者100例并按同期随机原则分为A^D 4组,每组25例。A^D组均采用相同的扫描条件;对比剂及生理盐水的注射速率均为4.5 mL/s。A组对比剂持续注射时间均为10 s,B^D组逐级减少1 s对比剂使用量,分别为9、8、7 s。采用Kruskal-Wallis检验比较各组主观图像质量评分;采用方差分析(ANOVA)比较各组图像CT值的差异。结果 A^C组显示了很好的主观对比度,评分均≥2分。D组与其他3组相比较差异有统计学意义(P<0.05)。D组左头臂静脉内无对比剂残留,与A、B两组相比较差异有统计学意义(P<0.05);C、D两组相比较无统计学差异(P>0.05)。尽管D组左头臂静脉内的CT值最低,但动脉内CT值出现低于250 HU的病例,且与A^C组相比较均存在统计学的差异(P<0.05)。结论在行经左侧上肢注射对比剂的头颈动脉联合CTA中,8 s的对比剂注射时间为最佳时间。

Objective To investigate the optimal injection time of the contrast media in 64 slice head-neck CTA injected from left upper extremity. Methods A total of 100 patients who would perform head-neck CTA were enrolled prospectively, and were randomly divided into four groups A to D, 25 cases in each group. All patients performed CTA with the same scan parameters and the same injection rate(4.5 mL/s) of the contrast media and the physiological saline. The injection time of the contrast media were 10, 9, 8 and 7 seconds from group A to group D, respectively. Kruskal-Wallis test was used to compare the subjective image quality scores of each group. Variance analysis(ANOVA) was used to compare the CT values of images in each group. Results Group A to C showed good subjective contrast with scores of no less than 2. There was significant difference between group D and other three groups(P<0.05). There was almost no contrast media in left brachiocephalic veins in group D. There was significant difference between group D and group A and B(P<0.05). There was no significant differences between group C and group D(P>0.05). Although the CT value in the left brachiocephalic vein was the lowest in group D, there were still cases in which the CT value in arteries was lower than 250 HU, and there were statistical differences compared with group A to C(P<0.05). Conclusion The optimal injection time of the contrast media is 8 seconds in 64 slice head-neck CTA injected from left upper extremity.