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目的探讨冠状动脉CTA时不同对比剂注射方案对图像质量的影响,优化注射方案。方法选取体重指数相似患者320例,分为A、B、C、D四组,进行冠状动脉CTA。A组对比剂采用双相注射方案,先期注射对比剂70 ml,而后注射生理盐水20 ml;B组采用双相注射方案,先期注射对比剂50 ml,而后注射混合液(生理盐水-对比剂1∶1)20 ml,C组采用三相注射方案,先期注射对比剂50 ml,第二时相注射混合液(生理盐水-对比剂1∶1)20 ml,而后无缝隙注射生理盐水20 ml;D组采用双相注射方案,先期注射对比剂50 ml,而后注射混合液(生理盐水-对比剂1∶1)20 ml,扫描时间较常规延迟5 s。比较四组冠状动脉CTA图像中冠状动脉三大分支和升主动脉(AO)CT值之间有无差异,比较四组上腔静脉、右心室硬化伪影发生率及室间隔显示率。结果与A组比较,B、C两组对比剂虽减少10 ml,但三组间AO及冠状动脉三大分支CT值比较无统计学意义(P>0.05),而D组CT值较A、B、C三组降低(P<0.05);B组上腔静脉、右心室硬化伪影发生率高于A、C、D三组(P<0.05),C、D两组室间隔显示率无统计学差异(P>0.05),但高于A、B两组(P<0.05)。结论采用三时相对比剂注射方案,可以有效降低对比剂用量,保证图像质量,清晰显示室间隔,为冠状动脉疾病的诊断提供影像依据。
Objective To investigate the effect of contrast medium injection on image quality in coronary CTA and to optimize the injection scheme. Methods 320 patients with similar body mass index were selected and divided into four groups: A, B, C and D for coronary CTA. Group A contrast agent using biphasic injection protocol, the initial injection of contrast agent 70 ml, and then injected saline 20 ml; B group using biphasic injection protocol, the initial injection of contrast agent 50 ml, and then injection mixture (saline - contrast agent 1 : 1) 20 ml. Group C was injected with 50 ml of contrast agent in the first phase and 20 ml of saline (contrast agent 1: 1) in the second phase. In group D, a biphasic injection protocol was used. Injections of 50 ml of contrast agent were injected in advance, followed by 20 ml of saline (contrast agent 1: 1). The scan time was 5 s longer than that of normal control. The differences between the three branches of coronary artery and the ascending aorta in four groups of coronary CTA images were compared. The incidences of superior vena cava and right ventricular septal artifacts and the rate of ventricular septum display were compared among the four groups. Results Compared with group A, there was no significant difference in the CT value of AO and coronary artery among the three groups (P> 0.05), but the CT value of group D was significantly lower than that of group A, (P <0.05). The incidence of superior vena cava and right ventricular cirrhosis in group B was higher than that in groups A, C and D (P <0.05), and the rates of ventricular septum in group C and D were no Statistical difference (P> 0.05), but higher than A, B two groups (P <0.05). Conclusion The three-phase contrast agent injection scheme can effectively reduce the contrast agent dosage, ensure the image quality and clearly show the ventricular septum, providing the imaging basis for the diagnosis of coronary artery disease.