低管电压与低对比剂量在肝脏CT增强中的应用

The Application of Lower Tube Voltage and Fewer Contrast Agents for Hepatic Enhanced CT Scanning

目的:探讨低管电压(110 kVp)与低对比剂量(1.0 mL/kg)在肝脏CT增强扫描中的可行性。方法:116例行肝脏CT增强扫描,且BMI<25kg/m^2的患者,随机分成A、B两组进行研究,每组58例。A组:管电压110 kVp,对比剂碘帕醇(300 mgI/mL),对比剂量(1.0 mL/kg),采用正弦迭代重建(SAFIRE)。B组:管电压130 kVp,对比剂碘帕醇(300 mgI/mL),对比剂量(1.2 mL/kg),采用滤波反投影重建算法(FBP)。测量动脉期腹主动脉CT值、肝门脉期门静脉CT值及增强扫描3期(动脉期、门脉期、延迟期)的肝右叶肝实质CT值;计算两组图像的肝动脉期对比噪声比(CNR)、信噪比(SNR)及总有效辐射剂量ED;并对两组图像进行评分,进行统计学分析。结果:A组和B组CNR、SNR差异无统计学意义(P>0.05);两组分别在增强扫描3期测得肝右叶肝实质CT值及动脉期腹主动脉CT值差异亦无统计学意义(P>0.05);肝门脉期A组的门静脉CT值低于B组统计学差异有意义(P<0.05)。A组的3期总有效辐射剂量(ED)(9.88±3.56)mSv低于B组(13.91±4.71)mSv,统计学差异有显著意义(P<0.001);A组比B组的对比剂量减少17%。结论:128层MSCT在肝脏增强CT扫描中,应用低管电压(110 kVp)和低对比剂量(1.0 mL/kg),联合迭代重建技术(SAFIRE),可以得到较好的图像质量,同时降低辐射剂量及人体碘摄入量。

Objective： To explore the feasibility of lower tube voltage （110kVp） and fewer contrast agent （1.0 mL/kg） for hepatic enhanced CT scanning. Methods： 116 cases of patients, BMI 〈 25, underwent hepatic enhanced CT scanning were randomly divided into two groups, 58 cases for each. Group A： tube voltage 110 kV, and contrast agent being iopamidol （300mgI/mL）, total contrast agent 1.0mL/kg, using sinogram affirmed iterative reconstruction （SAFIRE）. Group B： tube voltage 130 kV, and contrast agent being iopamidol （300mgl/mL）, total contrast agent 1.2 mL/kg, using filtered back projection （FBP）. Abdominal aorta CT value in aorta phase, portal vein CT value in portal vein phase and three-phase （aorta phase, portal vein phase, delay phase） of the right lobe were measured, then the contrast to noise ratio （CNR）, signal to noise ratio （SNR）, and effective radiation dose （ED） were recorded. All the images of the two groups were given subjective ratings, and the statistical analysis was made for all the above indicators between the two groups. Results： There were no significant difference in SNR and CNR between the two groups （P 〉 0.05, respectively）. There were no significant difference in the hepatic parenchymal CT value of the right lobe in three-phase and the abdominal aorta CT value in arterial phase between the two groups （P 〉 0.05, respectively）. The portal vein CT value of group A was lower than that in group B （P 〈 0.05, significantly）. The total ED of three-phase in group A was （9.88 ± 3.56） mSv, it was lower than group R, （13.91 ±4.71）mSv （P 〈 0.001, significantly）. Compared with group B, the total contrast agent dose of group A was reduced by 17%. Conclusion： In hepatic enhanced CT scanning, when using lower tube voltage （110 kVp）, fewer contrast dose （1.0 mL/kg）, and simultaneous iterative reconstruction technique with 128 slice spiral CT, it can provide better image quality, and reduce the ED and iodine intake of the human body.