64排CT低管电压低剂量对比剂联合0.9%氯化钠溶液在CT肺动脉造影中的应用

Low tube voltage and low dose contrast agent combined with normal saline in 64 row CT pulmonary angiography:a preliminary study

目的:探讨64排CT低管电压低剂量对比剂联合0.9%氯化钠溶液在CT肺动脉造影(CTPA)中的应用价值。方法:采用实验性研究,将临床怀疑为肺动脉病变而行CTPA检查的60例患者随机分为对照组和实验组(n=30),采用64排CT进行CTPA检查。对照组管电压为120kVp,对比剂用量60mL;实验组管电压为80kVp,对比剂用量为40mL,并联合0.9%氯化钠溶液20mL。其余扫描条件相同。比较2组图像肺动、静脉CT值、图像背景噪声、信噪比(SNR)、对比噪声比(CNR)、CT剂量指数(CTDIvol)、剂量长度乘积(DLP)、有效剂量(ED)的差异,并比较2组图像主观评分差异。结果:60例中顺利完成检查54例(对照组和实验组分别28例和26例),实验组的肺动脉CT值、图像背景噪声、SNR、CNR均高于对照组(P<0.05),而肺静脉CT值、CTDIvol、DLP、ED均低于对照组(P<0.05)。2组图像质量的主观评分差异无统计学意义(P>0.05)。结论:64排CT低管电压下低剂量对比剂联合0.9%氯化钠溶液行CTPA可获得满意的图像质量,并可显著降低辐射剂量和对比剂用量。

Objective： To explore the applied value of low tube voltage and low dose contrast agent com-bined with normal saline in 64 row CT pulmonary angiography. Methods： An experimental study was carried out in 60 patients suspected of pulmonary artery disease by clinic and required CTPA, who were randomly divided as control group and experimental group, with 30 cases in each group. All patients accepted pulmonary artery CTPA by 64 row CT. In control group, tube voltage was 120 kVp, contrast dose was 60 mL, while in experimental group, tube voltage was 80 kVp and contrast dose was 40 mL combined with 20 mL of normal saline, the other parameters being all the same. Independent t-test was used to compare the CT values of pulmonary artery and pulmonary vein, image noise, signal-to-noise ratio （SNR）, contxast-to-noise ratio （CNR）, volume CT dose index （CTDIvol）, dose length product （DLP）, effective dose （ED）. Chi square test was used to compare the subjective quality between two groups of images. Results： Among 60 patients, 54 completed the examination successfully （28 cases in control group and 26 cases in experimental group）, CT values of pulmonary artery, image noise, SNR, CNR of experimental group were higher than those of control group （P〈0.05）, while CT values of pulmo- nary vein, CTDIvol, DLP, ED were lower than those of control group （P〈0.05）, and there was no significant dif- ference in subjective image quality between two groups （P〉0.05）. Conclusion： Low tube voltage and low dose contrast agent combined with normal saline in 64 row CT pulmonary angiography can produce satisfactory image quality and remarkably decrease the radiation dosage and contrast dose.