64排螺旋CT肺CTPA成像低剂量造影剂的应用研究

目的:研究64排螺旋CT肺动脉造影中低剂量造影剂对临床疑似肺栓塞患者诊断的可行性,进一步优化肺动脉造影中造影剂的使用剂量。方法:对临床怀疑肺动脉栓塞且心功能未见异常的患者40例,将其随机分为A、B两组,采用对比剂自动跟踪触发技术即(Smart prep监控技术)行CT肺动脉血管造影(CTPA)检查。A组选用非离子对比剂造影剂碘海醇370mgI/ml,剂量80ml,注射流率4ml/s。B组选用相同造影剂30ml,注射流率4ml/s。对比剂注射结束后,随即以相同速率注射40ml生理盐水,两组病例CT扫描参数相同。对两组不同剂量造影剂成像后的断面图像进行分析,影像评价标准按5级行盲法评价:1级2级为不合格,3级为合格,4级5级为优秀。结果:两组不同剂量造影剂CTPA影像质量评价显示,图像质量没有显著性差异;肺动脉主干及分支血管内浓度的测量CT值差异评价显示均良好,40ml低剂量组血管内浓度均维持在较高的水平,统计学上与80ml组无显著性差异,两组图像都可达到诊断要求。结论:64排螺旋CT肺动脉血管成像中,降低造影剂的注射量,对图像质量没有影响。

On the application of 64-slices helical CT pulmonary angiography with low dose contrast agent

Objective: To study the feasibility of 64-slices helical CT pulmonary angiography(CTPA) with low dose contrast agent in diagnosing the clinical suspected pulmonary embolism(PE) patients so as to further optimize the contrast agent dose in CTPA.Methods: 40 patients with suspected pulmonary embolism and normal heart functions were randomly divided into two groups: Group A and B.Smart prep monitoring technology was used to perform CTPA test on the two groups.80 ml non-ion contrast agents iohexol enhancement scanning was applied to patients in Group A with the concentration of 370 mgI/ml and with the injection flow rate of 4 ml/s,while 30 ml of the same contrast agent and with the same injection flow rate were used in patients in Group B.After the injection of contrast agent,40 ml saline was injected into the patients in both groups at the same injection flow rate.The parameter of CT scanning was the same in cases of both groups.The cross-section images by different dosage of agents were analyzed.And the image evaluation standard were divided into 5 levels according to blind evaluation method,level 1~2 was regarded as unqualified,level 3 as qualified and level 4~5 as fine.Results: The CTPA image quality evaluation of patients in both groups showed that there was no difference in image quality.And the main pulmonary artery and the branch intravascular concentration measurement showed that CT value difference evaluation of both groups was good.The intravascular concentration remained high level in low dose group of 40 ml agent,compared with the high dose group of 80 ml agent,there was no statistical difference.The image attained in both groups met the diagnostic requirement.Conclusion: In the 64-slices helical CT pulmonary angiography(CTPA),the reducing of injection of contrast agent won’t affect the quality of the images.