循环时间对冠状动脉CTA对比剂使用剂量选择的应用研究

Application study on effects of circulation time on coronary CTA contrast agent dose selection

目的:比较64层螺旋CT使用不同方法计算对比剂剂量对冠状动脉显影质量的影响,探讨在保证图像质量的前提下,使用最少量对比剂的方法,研究新的计算对比剂剂量方法。方法:选择收治的疑似冠状动脉疾病患者200例,分别经肘或手背静脉团注不同剂量的对比剂;其中100例使用经验值70 ml或80 ml或(体重×0.9)ml,100例使用新方法计算对比剂使用量;造影剂为碘海醇(350 mgl/ml)注射液,注射速率5.0 min/s或5.5 min/s,随后相同速率注射50 ml生理盐水。扫描范围气管隆突下1 cm至心脏膈面下2 cm。结果:比较两组患者冠状动脉开口处升主动脉的CT值,差异无统计学意义(P>0.05),比较两组患者的冠状动脉图像质量,差异无统计学意义(P>0.05),比较两组患者的对比剂使用剂量,差异有统计学意义(P<0.05)。采用OPTIMA 660 64层螺旋CT机,回顾性心电门控扫描,120 k V,管电流(ECG modulated MA 450~560 m A),重建模式(Snap Shot Segment),迭代设置(ss40 slice 40%),探测器宽度40.0 mm,层厚0.625 mm。结论:根据对比剂循环时间确定对比剂用量的方法是完全可行的,既提高了图像的质量,又节省了造影剂剂量。

Objective： To compare effects of contrast agent dosage calculated by using different methods in 64-slices spiral CT on development quality,and to study a new calculation method of contrast agent dosage under the guarantee of image quality by using the least contrast agent. Methods： 200 admitted patients with suspected coronary artery diseases were selected and injected with different dosed of the contrast agentthroughelbow vein or the dorsal hand vein,wherein,100 cases used the empirical value 70 ml or 80ml（ body weight ×0.9） ml,while 100 examples used the doses calculated by the new method. The contrast agent was Lohexolinjection（ 350mgl/ml）,and the injection rate was 5. 0 min/s or 5. 5 min/s. Then,50 ml physiological saline was injected with the same rate. The scanning scope was from 1cm below tracheal carina to 2cm below heart diaphragmatic surface. Results： There was no statistical difference in the coronary ostium ascending aorta CT value between the two groups（ P〉0.05）. Also,there was no difference in the coronary artery image quality between the two groups（ P〉0.05）. The difference of the contrast agent dosages between the two groups was statistically significant（ P〈0.05）. OPTIMA 660 64-slices spiral CT machine and retrospective ECG-gating scanning technique were used with 120 KV,manages electric current（ ECG modulated MA 450-560 m A）,recon mode（ Snap Shot Segment,ASiasetup（ ss40 slice40%）,detector coverage40.0mm,andhelical thickness 0.625 mm. Conclusion： it is feasible to determine the dosage of contrast agents according to the cycle time of contrast agents. It can not only improve the image quality,but also save the contrast dose.