低剂量CT结合自适应统计迭代重建测量体模肺结节  

Low dose CT combined with adaptive statistical iterative reconstruction for measuring phantom lung nodules

作　　者：段海峰 贾永军[1] 马光明 张喜荣 陈静 樊丽华 于楠 杨创勃 DUAN Haifeng;JIA Yongjun;MA Guangming;ZHANG Xirong;CHEN Jing;FAN Lihua;YU Nan;YANG Chuangbo(Department of Radiology,Affiliated Hospital of Shaanxi University of Chinese Medicine,Xianyang 712000,China;Department of Radiology,the First Affiliated Hospital of Xi’an Jiaotong University,Xi’an 710061,China;College of Medical Technology,Shaanxi University of Chinese Medicine,Xianyang 712000,China)

机构地区：[1]陕西中医药大学附属医院医学影像科,陕西咸阳712000 [2]西安交通大学第一附属医院影像科,陕西西安710061 [3]陕西中医药大学医学技术学院,陕西咸阳712000

出　　处：《中国医学影像技术》2021年第2期278-283,共6页Chinese Journal of Medical Imaging Technology

基　　金：国家自然科学基金(81701691);陕西中医药大学创新团队项目(2019-QN09、2019-YS04)。

摘　　要：目的观察低剂量CT(LDCT)测量仿真体模肺部不同大小、密度结节的影响因素。方法于仿真肺体模中随机放置9个大小、密度均不同的人工球形结节。噪声指数固定为14,分别以不同权重前置自适应统计迭代重建(ASIR)调整扫描管电流行CT扫描,重建60%后置ASIR薄层肺算法图像。于轴位图上测量结节最大截面长径、短径,计算长短径误差和失圆度,比较不同剂量下不同密度肺结节长短径误差及失圆度。采用4分法评价不同辐射剂量条件下各肺结节清晰光滑度及失真度。结果不同剂量重建图像检出肺结节的敏感度均为100%。结节密度影响结节长短径误差及失圆度,且对磨玻璃结节尤著。辐射剂量影响结节长短径误差及失圆度,随辐射剂量减低,结节长短径误差及失圆度增大,且40%、60%前置ASIR条件下长短径误差、失圆度与常规剂量扫描存在差异,60%前置ASIR条件下长短径误差与20%存在差异。辐射剂量和结节密度影响肺结节清晰光滑度、失真度;在低剂量条件下磨玻璃结节清晰光滑度及失真度评分降低,且辐射剂量越低评分越低,辐射剂量差≥40%时,各结节间噪声与清晰度、失真度评分差异均有统计学意义(P均<0.05)。结论LDCT检出仿真体模结节的敏感性高,但过度降低辐射剂量将致肺结节边界清晰度下降和结节形态失真,对磨玻璃结节影响更大。Objective To observe the impact factors of low-dose CT(LDCT)on measurement of different sized and shaped pulmonary nodules with different densities.Methods Nine artificial spherical nodules with different sizes and densities were randomly placed inside a virtual lung phantom.The noise index was fixed as 14,the prescribed adaptive statistical iterative reconstruction(ASIR)with different weights were used to adjust CT scanning,and thin-layer lung images of the post ASIR were reconstructed.The long and short diameter on the maximum sections of the nodules were measured on the axial images of the post-processing workstation,and the long-short diameter error and out-of-roundness of pulmonary nodules with different densities at different doses were compared.Then 4-point method was used to evaluate the clear smoothness and distortion of each nodule under different radiation doses,and the consistency of scoring were compared and analyzed.Results The detection sensitivity of nodules was all 100%under different radiation doses.Nodule density affected the long-short diameter error and out-of-roundness in LDCT,and ground glass nodules(GGN)were impacted more obviously than solid nodules.Radiation dose affected the long-short diameter error and out-of-roundness of each nodule.With the decrease of radiation dose,the long-short diameter error and out-of-roundness of each nodule increased,and there were significant differences of long-short diameter error and out-of-roundness of nodules among the condition of 40%and 60%prescribed ASIR and conventional dose scanning,also of long-short diameter error between 60%prescribed ASIR and 20%.Radiation dose and nodule density affected the clarity,smoothness and distortion of nodules,and the lower the radiation doses,the lower the scores.When the difference of radiation dose was≥40%,the difference of noise,clarity and distortion of nodules were statistically different(all P<0.05).Conclusion LDCT had high sensitivity of detecting artificial spherical nodules,but excessive reduction of radi

关 键 词：肺 结节 体模 显像术 体层摄影术 X线计算机 

分 类 号：R563[医药卫生—呼吸系统] R814.42[医药卫生—内科学]