儿童胸部低剂量CT扫描中最佳KARL迭代重建等级的研究  

Study of Best KARL Iterative Reconstruction Level in Children's Chest Low Dose CT Scanning

作　　者：赵凡惠 王雷 李建龙[1] 郭佑民[1] 黄晓旗 ZHAO Fan-hui;WANG lei;LI Jian-long(Department of Image,The Affiliated Hospital of Yan'an University,Yan'an 716000,Shaanxi Province,China)

机构地区：[1]延安大学附属医院影像科,陕西延安716000

出　　处：《中国CT和MRI杂志》2020年第11期55-58,F0002,共5页Chinese Journal of CT and MRI

基　　金：延安市科技攻关计划项目(编号:2018KS-11);延安市科技惠民计划(编号:2017-HM-07-01)。

摘　　要：目的比较不同KARL迭代重建等级(1~9级)对儿童胸部低剂量CT图像噪声和质量的影响,寻找不同年龄段儿童图像重建的最佳迭代等级。方法回顾性分析90例儿童胸部低剂量CT图像,按年龄分为三组,分别为0~12个月组,1~2岁组,3~6岁组。将原始数据进行肺窗和纵隔窗的KARL迭代重建(1~9级)和滤波反投影法重建,共得到20组重建图像。分别测量各组图像肺动脉分叉层面升主动脉的CT值及噪声值,计算信噪比。同时由两名医师对图像质量进行主观评分,≥3分为满足诊断需求的图像。通过单因素方差分析,均数间差别多重比较采用LSD检验,比较各年龄组不同KARL迭代等级的图像质量差异。结果滤波反投影法重建图像和不同等级KARL迭代图像的噪声值、信噪比差异有统计学意义,CT值差异无统计学意义。随着KARL迭代等级的增高,信噪比增高,噪声减低。0~12个月组最佳迭代等级肺窗为5,纵隔窗为4。1~2岁组和3~6岁组图像最佳迭代等级肺窗为6,纵隔窗为5。结论在儿童胸部低剂量CT扫描中,KARL迭代重建技术可降低图像噪声,提高图像质量,迭代等级为4~6时图像质量最好。Objective To compare the quality and noise of children's chest low-dose CT images which reconstructed by different KARL levels(1 to 9),to find the best iterative reconstruction level of children in different age groups.Methods A total of 90 children's chest images scanned by low dose CT were analyzed retrospectively,and were divided into three groups according to age,set to 0 to 12 months old,1 to 2 years old,3 to 6 years old.The original data of lung and mediastinal window reconstructed by different KARL iterative reconstruction levels(1 to 9)and filter back projection,received 20 groups of reconstruction image,measured ascending aorta's CT and noise value in pulmonary artery branch level,calculated the signal-to-noise ratio.The subjective images were assessed by two radiologists,images of 3 points or higher could meet the demand of diagnostic.Through the single factor analysis of variance,mean difference between multiple comparison of LSD test to compare the differences between different KARL iteration levels and image quality in different age groups.Results Image noise and signal-to-noise ratio are different between different iterative reconstruction levels,there was no difference between CT values.As KARL iteration level higher,signal-to-noise ratio is higher but image noise is lower.To 0 to 12 months group,the best iterative reconstruction level for lung window image is 5 and for mediastinal window is 4,to 1 to 2 and 3 to 6 years old group,the best iterative reconstruction level for lung window image is 6 and for mediastinal window is 5.Conclusion In children's chest low-dose CT scan,the application of KARL iterative reconstruction technique can reduce the noise and improve the quality of image significantly,the best iterative reconstruction level is 4 to 6.

关 键 词：儿童 胸部 低剂量CT X线计算机 迭代重建技术 

分 类 号：R814[医药卫生—影像医学与核医学] R734[医药卫生—放射医学]