低电压小剂量对比剂在主动脉CT血管造影检查的可行性研究

目的：探讨64排CT进行大范围动脉血管检查应用低电压、小剂量对比剂的可行性。方法：前瞻性将72例行主动脉血管CT血管造影（CTA）检查患者随机分为A组20例、B组32例和C组20例。各组扫描参数、对比剂用量分别为A组：120 kV、260 mA、80 mL;B组：120 kV、260 mA、50 mL;C组：80 kV、260 mA、50 mL。比较并统计各组间肝门水平位置的主动脉部强化程度从而评估图像质量以及有效吸收剂量的差异。结果：主动脉CT值超过200 HU的峰值持续时间为（10±4）s。动脉平均增强CT值,A组大于B组,B组大于C组,但没有统计学差异,图像质量A、B、C 3组均能满足诊断要求。患者有效吸收剂量C组明显低于A、B两组（P〈0.01）。结论：应用64排CT进行主动脉血管检查,使用小剂量对比剂及低管电压可行,图像质量满足诊断需要,患者的吸收剂量下降。

Feasibility of low radiation and low dose contrast agent in aorta CT angiography

Objective： To investigate the feasibility of long extension arterial examination using low tube voltage setting and low dose contrast agent on 64-row detector CT. Methods：The patients were enrolled into 3 groups. Twenty patients in group A were examined by conventional protocol with 80 mL contrast medium at 120 kV voltage. Thirty two patients in group B were injected contrast medium of 50 mL at 120 kV voltage. Twenty patients in group C were injected contrast medium of 50 mL at 80 kV voltage. The aorta vascular structure was also scanned. The time of CT value in abdominal aorta that exceeded 150 HU and 200 HU were recorded. The average CT value of artery enhancement, image Signal-to-Noise, and available absorbed dose were compared among group A,B and C. Results： The mean intraluminal attenuation of group A and B were higher than that of group C（P〈0.05）. The mean intraluminal attenuation of group C was higher than that of group A（P〈0.05）. The image Signal-to-Noise of group A and B were higher than that of group C. The available absorbed dose of group C was significantly lower than those of group A and B. Conclusion：The image quality of the aorta vascular structure examination on 64-row detector CT using low dose contrast medium is feasible. The images are proper for diagnose and the dose of contrast medium has been reduced.