迭代模型重建技术参数设置对肝脏低剂量增强CT扫描图像质量的影响  

Impact of reconstruction parameter settings of knowledge-based iterative model technique on image quality of low-dose hepatic contrast-enhanced CT

作　　者：樊荣荣[1] 施晓雷 张天然 钱懿[1] 陈如谭[1] 范丽[1] 萧毅[1] 

机构地区：[1]第二军医大学长征医院影像科,上海200003

出　　处：《中国医学影像技术》2017年第11期1711-1715,共5页Chinese Journal of Medical Imaging Technology

摘　　要：目的探讨全模型迭代重建(IMR)技术不同参数设置对肝脏低剂量增强CT扫描图像质量的影响。方法收集需要接受肝脏增强CT检查的患者40例,分别行上腹部平扫和3期动态增强扫描,其中延迟期采用低剂量扫描,管电压80kV,管电流150mAs。对原始数据进行滤波反投射(FBP)重建和IMR技术重建,IMR采用不同参数,以获得不同水平(Level 1~3)的常规和软组织重建图像,分别记为R1、R2、R3亚组和S1、S2、S3亚组。对各组图像进行主观和客观评价并比较,主观评价包括低对比分辨率(LCD)、图像失真(ID)和诊断信心(DC)评分,客观评价包括肝脏噪声、信噪比(SNR)和对比噪声比(CNR)。结果不同参数组图像的LCD、ID和DC评分差异均有统计学意义(P均<0.01)。不同参数组图像间噪声、SNR及CNR差异均有统计学意义(P均<0.01);除S1与R2亚组、S2与R3亚组3项指标(P均>0.05)外,余两两比较差异均有统计学意义(P均<0.01)。结论全迭代重建IMR技术可提高肝脏低剂量增强CT扫描的图像质量,推荐参数为软组织重建、Level 1或常规重建、Level 2。Objective To evaluate the impact of different reconstruction parameter setting of knowledge-based iterative model reconstruction（IMR）technique on image quality of low-dose hepatic contrast-enhanced CT.Methods Forty patients underwent hepatic contrast-enhanced CT scanning were enrolled.Plain CT and triphasic contrast-enhanced CT scans,including hepatic arterial phase,portal-venous phase and delayed phase were performed.Low-dose scan was used in delayed phase,with tube voltage of 80 kV and tube current of 150 mAs.Images of delayed phase were reconstructed with both filtered back projection（FBP）and IMR techniques.Parameter setting applied in IMR reconstructions consisted of body routine and body soft tissue modes with three 1 evels（Level 1—3）,so 6 subgroups（R1,R2,R3,S1,S2,S3）were included.Subjective and objective evaluations of image quality were compared among those groups.Subjective evaluations included the scores of low contrast detectability（LCD）,image distortion（ID）and diagnostic confidence（DC）.Objective evaluations included image noise,signal to noise ratio（SNR）and contrast to noise ratio（CNR）.Results There were statistical differences of scores in LCD,ID and DC among all the reconstruction parameter setting groups（all P0.01）.The noise,SNR and CNR among different parameter setting groups had statistically significant differences（all P0.01）.Except for subgroup S1 and subgroup R2,subgroup S2 and subgroup R3（all P0.05）,the other multiple comparisons showed significant differences（all P0.01）.Conclusion IMR can improve image quality of low-dose hepatic contrast-enhanced CT.IMR reconstruction parameter setting of S1 and R2 are optimal for low-dose hepatic contrast-enhanced CT protocal.

关 键 词：肝脏 体层摄影术 X线计算机 图像质量 

分 类 号：R575[医药卫生—消化系统] R814.42[医药卫生—内科学]