低剂量扫描联合低剂量对比剂在CT肺动脉成像应用

Low radiation dose combined with low-dose contrast medium on spiral CT pulmonary artery angiography

目的:探讨低剂量扫描联合低剂量对比剂在多层螺旋CT肺动脉成像(CTPA)的应用。方法:60例临床疑似肺栓塞的患者随机分为A、B两组,每组各30例。A组为试验组,扫描管电压为80kVp,对比剂采用碘海醇(300mg/mL)35mL及30mL0.9%氯化钠溶液。B组为对照组,扫描管电压为120kVp,对比剂采用碘海醇(300mg/mL)70mL及0.9%氯化钠溶液30mL。测量肺动脉主干至双侧亚段肺动脉的CT值,计算平均CT值。以肺动脉主干CT值的标准差代表图像噪声,记录CT实际容积剂量指数(CTDIvol)、剂量长度乘积(DLP)、并计算有效剂量(ED)。计算图像信噪比(SNR)及对比噪声比(CNR),对图像质量进行五级评分。结果:A组CDTIvol、DLP、ED分别为(6.21±0.89)mGy,(239.28±1.78)mGy·cm,(3.46±0.87)mSV。B组CDTIvol、DLP、ED分别为(12.07±1.38)mGy,(451.42±2.98)mGy·cm,(6.31±1.06)mSV。两组辐射剂量差异有统计学意义(P<0.05),A组患者的辐射剂量明显比B组降低46%。两组图像质量主观评分差异无统计学意义(P>0.05)。结论:应用低管电压联合低剂量造影剂在CTPA中是完全可行的,可以在保证图像质量的情况下明显降低的患者的辐射剂量和对比剂的用量。

Objective：To study the value of Low radiation dose scanning combined with low-dose con- trast medium on spiral CT pulmonary artery angiography. Methods： Sixty patients who suspected Pulmonary embolism were randomLy assigned to 2 groups, with 30 patients in each group. The comparison group was injec- ted Non-ionic contrast agent 35 mL and 30 mL NS, with tube voltage as 80kVp. The test group was injected Non-ionic contrast agent 70 mL and 30 mL NS, with tube voltage as 120kVp. The CT value was measured from the puhnonary artery to the bilateral pulmonary subsegment. The mean CT value was calculated. The image noise was the standard deviation of the CT values of the pulmonary trunk. The actual volume CT dose index （CTDIvol） , the dose length product（DLP） and the effective dose （ED） were recorded. Results： The CTDIv- ol, DLP and ED of Group A were （ 6. 21 ± 0. 89 ） mGy, （239. 28 ± 1.78 ） mGy cm, （3.46 ± 0. 87 ） mSV. The CTDIvol, DLP and ED of Group B were （ 12. 07 ± 1. 38 ） mGy, （451.42 ± 2. 98 ） mGy · cm, （ 6. 31 ± 1.06 ） mSV. The difference was statistically significant between the two groups of radiation dose. Group A was descen- ded 46% of radiation dose to Group B. Conclusion： Low radialion dose scanning combined with low-dose con- trast medium on multislice spiral CT pulmonary artery angiography are feasible. The method can reduce the ra- diation dose and the contrast agents dose for the patients obviously with ensuring the image quality.