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目的探讨心功能不全(II-IV级)患者640层CT冠状动脉成像的可行性,比较不同触发技术对升主动脉根部强化程度、对比剂用量及所受辐射剂量的影响。方法 640层容积CT冠状动脉成像的49例心功能不全患者,先行小剂量测试,获得达峰时间(T1),再行自动跟踪手动触发扫描,获得手动触发时间(T2),比较两者时间的差异。根据心功能等级,将49例病例分为S组(心功能II级)和N组(心功能III-IV),比较两组T1、T2及升主动脉根部的CT值的差异。所有数据经整理后,使用SPSS17.0进行统计分析。结果 49例心功能不全患者的T1为(25.9±6.0)s,T2为(26.2±5.6)s,经配对t检验两者间差异无统计学意义(P>0.05)。不同心功能分组间的T1时间、T2时间差异均有统计学意义,但触发时间差值T(T=T1-T2)无统计学意义。自动跟踪手动触发所使用的对比剂用量(47.7±6.2)ml,较联合应用小剂量测试所用的对比剂总量(67.3±7.0)ml,有显著的减少(P<0.005),并且辐射剂量减少33%～86%。结论心功能不全患者的循环时间平均为26 s左右,小剂量测试扫描技术和自动跟踪手动触发技术均能很好的选择触发时机,尤其后者更具有减少对比剂用量的优势。
Objective To investigate the feasibility of 640-slice CT coronary angiography in patients with cardiac insufficiency (grade II-IV) and compare the effects of different triggering techniques on the degree of root reinforcement, contrast medium dosage and radiation dose in ascending aorta. Methods Forty-nine patients with cardiac dysfunction who underwent coronary angiography with 640-slice volume CT were given low-dose test at first, and then reached the peak time (T1). Then manual trigger scanning was performed automatically to obtain the manual triggering time (T2) difference. According to the level of cardiac function, 49 cases were divided into S group (cardiac function class II) and N group (cardiac function III-IV). The differences of CT value between T1, T2 and ascending aortic root were compared between the two groups. After finishing all the data, using SPSS17.0 for statistical analysis. Results Twenty-nine patients with cardiac insufficiency had T1 of (25.9 ± 6.0) s and T2 of (26.2 ± 5.6) s. There was no significant difference between the two groups (P> 0.05). There were significant differences in T1 time and T2 time between different cardiac function groups, but the difference of trigger time T (T = T1-T2) was not statistically significant. The amount of contrast agent used in manual triggering was 47.7 ± 6.2 ml compared with 67.3 ± 7.0 ml for the low-dose combination test (P <0.005) and the radiation dose was decreased 33% ~ 86%. Conclusions The mean circulatory time of patients with cardiac insufficiency is about 26 s. The low-dose test and automatic manual triggering technology can all choose the triggering time, especially the latter has the advantage of reducing the dosage of contrast medium.