低辐射剂量和低对比剂用量在门静脉血管成像技术的应用

Applications of Low Radiation Dose and Low Contrast Agent in Portal Vein Vascular Imaging

目的应用双能量扫描模式进行门静脉期图像采集,并用融合系数重建模式进行门静脉期图像重建,实现在低剂量、低造影剂下获得最佳门静脉血管的图像。方法选取进行门静脉血管成像的病人60例,随机分为A、B两组,每组30例。A组采用双能量扫描,造影剂用量1 m L/kg。B组采用常规120 k V,造影剂用量1.2 m L/kg。对各组所得图像进行分析,并测量门静脉CT值,噪声,计算SNR、CNR。由两位放射科医师对两组图像质量进行5分评价。对所得到的图像数据运用SPSS 17.0软件进行统计学分析。结果A和B组的门静脉强化CT值分别为175 HU以上和124 HU以上,两组间有统计学差异性。A组所得图像在图像质量方面较B组常规组有明显的提高,图像得分均明显高于B组。A组图像得分(4.4±0.5),B组得分(3.8±0.38),低于A组,P值<0.05,差异有统计学意义。A组在辐射剂量明显低于B组,较B组降低35%。结论采用双能量扫描并进行融合图像模式重建图像,可以获得高质量的门静脉血管图像且辐射剂量得到降低,对比剂用量减少近35%,而门静脉血管平均CT值较常规组提高60 HU以上,值得临床推广。

Objective To obtain optimal images for portal vein blood vessels under low radiation dose and low contrast agent condition,the present study performed image capturing via application of dual-energy portal venous phase scan mode,as well as reconstructing images via fusion coefficient reconstruction model.Methods Sixty patients that were going to undergo portal vein angiography were randomly divided into A,B groups,and each group contained30cases.Group A was conducted dual-energy scanning with the dosage of contrast agent of1mL/kg.Group B was conducted normal scanning with the traditional single energy of120kV,the contrast agent dosage of1.2mL/kg.The CT value of the portal vein and the noise of the images were measured,the value of the SNR and CNR were calculated.In addition,the quality of the images was evaluated by two radiologists under a model of five points.Finally,SPSS17.0software were utilized to conducting statistical analysis on the data of the images.Results The CT value of the portal vein Group A and group B were separately more than175HU and124HU.There was a statistical difference between these two groups.Compared with group B,the image quality of group A was obviously improved,and the image scores were significantly higher than that of group B.The image score of group A was(4.4±0.5),and the image score of group B was(3.8±0.38).It was statistically significant between these two groups(P<0.05).The radiation dose of group A was lower than that of group B,with a decrease of35%.Conclusion High quality of portal vein blood vessel image could be obtained by using double energy scanning and fusion coefficient reconstruction model to reconstructed images.Meanwhile,the radiation dose was lower and the contrast agent dosage was decreased nearly by35%.However,compared with the traditional single energy scanning,the portal vein blood vessels average CT value of the dual-energy scanning was increased by more than60HU.Therefore,it is worthy of clinical expansion.