双低扫描联合正弦波迭代重组技术在肝脏增强CT扫描的可行性研究

Feasibility study of double low scan combined with sinogram-affirmed iterative reconstruction in liver contrast-enhanced CT scan

目的探讨联合低剂量碘对比剂、低管电压和正弦波迭代重组(SAFIRE)技术用于肝脏增强CT扫描的可行性。方法收集2016年6月1日—7月31日行双源CT肝脏增强扫描(包括动脉期和静脉期)的病人200例,男118例,女82例,年龄21~82岁,平均(57.1±12.2)岁。病人随机分为2组:A组(100例)采用管电压100 kV和SAFIRE重组,对比剂剂量400 mg/kg;B组(100例)采用管电压120 kV和滤过反投影法重组,对比剂剂量500 mg/kg。采用两独立样本t检验比较影像质量评分、噪声、对比噪声比(CNR)、对比剂剂量和辐射剂量。结果 A、B组肝脏动脉期和门静脉期的影像质量评分,影像噪声,腹主动脉、门静脉和肝实质的CNR差异均无统计学意义(均P>0.05)。A、B组动脉期有效辐射剂量分别为(3.21±0.63)mSv和(4.08±1.16)mSv(P<0.05),A组较B组低21.3%;静脉期有效辐射剂量分别为(3.12±0.36)mSv和(3.88±1.11)mSv(P<0.05),A组较B组低19.6%。结论与常规120 kV肝脏增强CT扫描相比,低剂量碘对比剂、100 kV低管电压和SAFIRE重组技术可以在保持肝脏影像质量不降低的基础上,降低有效辐射剂量。

Objective To evaluate the feasibility of using lower contrast dose,lower X-ray tube voltage and sinogram affirmed iterative reconstruction(SAFIRE)technique in liver contrast-enhanced CT scan.Methods This study included 200 patients(57.1±12.2 years old,range 21 to 82 years;118 males,82 females).Each patient underwent hepatic arterial phase(HAP)and portal venous phase(PVP)hepatic dynamic CT in dual-source CT collected during June 1,2016 to July 31,2016.Patients were randomly divided into two groups.In the A group(n=100),100 kV,400 mg/kg Iodixanol and sinogram affirmed iterative reconstruction was applied;In the B group(n=100),120kV,500 mg/kg Iodixanol and filtered back projection reconstruction was applied.Image quality scores,image noise,contrast-to-noise-ratio(CNR),contrast dose,and effective radiation dose were compared with two sample t tests between the two groups.Results Between the two groups,there were no significant differences in the image quality scores at hepatic arterial phase and portal venous phase,image noise,contrast-to-noise ratio(CNR)of abdominal aorta,CNR of portal vein,and CNR of hepatic parenchyma(all P>0.05).The effective radiation dose was 21.3%lower in the group A than the group B at HAP,and 19.6%lower at PVP(HAP:3.21±0.63 mSv vs.4.08±1.16 mSv;PVP:3.12±0.36 mSv vs.3.88±1.11 mSv).The differences were statistically significant(all P<0.05).Conclusion Lower contrast dose,low tube voltage(100 kV)and the sinogram-affirmed iterative reconstruction technique could decrease radiation dose and provide adequate image quality compared with conventional(120 kV)hepatic contrast enhanced CT.