基于KARL迭代算法对COPD低剂量CT扫描条件下肺气肿定量测量的影响  

Effect of KARL iterative reconstruction on quantitative measurement of emphysema under low-dose CT scan of COPD

作　　者：黄晓旗 祁鑫华[1] 王雷 赵凡惠 朱彦瑾 刘文秀[1] 郭佑民[2] HUANG Xiaoqi;QI Xinhua;WANG Lei;ZHAO Fanhui;ZHU Yanjin;LIU Wenxiu;GUO Youmin(Department of Medical Imaging, The Affiliated Hospital of Yan'an University, Yan'an 716000;Department of Imageology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China)

机构地区：[1]延安大学附属医院影像科,陕西延安716000 [2]西安交通大学第一附属医院影像科,陕西西安710061

出　　处：《西安交通大学学报（医学版）》2020年第3期410-414,467,共6页Journal of Xi’an Jiaotong University（Medical Sciences）

基　　金：《基于数字肺的呼吸系统疾病评价体系与诊断标准研究》公益性行业科研专项基金(No.201402013);北京市自然科学基金资助项目(No.7182149);国家重点研发计划(No.2016YFC0905600);延安市科技惠民计划(No.2017-HM-07-01);延安市科技攻关计划项目(No.2018KS-11)。

摘　　要：目的探讨KARL迭代重建算法在低剂量与常规剂量扫描条件下对慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)患者肺气肿指数定量的影响。方法前瞻性收集我院2018年6月—2019年3月符合肺功能诊断的伴肺部结节COPD患者30例,其中男性25例,女性5例。采用联影uCT-760128排螺旋CT对30例患者首次检查进行常规剂量(120 kV,150 mAs)扫描,复查患者进行低剂量(120 kV,80 mAs)扫描。常规剂量采用滤波反投影(filtered back projection,FBP)重建,低剂量采用FBP与KARL迭代算法重建,计算有效辐射剂量(ED),在肺动脉分叉层面计算升主动脉CT值与噪声(SD值)并计算信噪比(SNR)。将3组扫描原始数据导入“数字肺”检测及分析平台,计算出肺气肿体素指数(EI)、全肺容积(LV)及全肺平均肺密度(MLD)。采用配对样本t检验分析图像CT值、SD、SNR与CT定量指标差异。Bland-Altman分析计算肺气肿平均测量偏差与两种测量方法的一致性。结果常规剂量和低剂量有效辐射剂量分别为(6.91±0.53)mSv和(3.71±0.28)mSv,下降约47%(P<0.001)。常规剂量FBP组与低剂量FBP组LV、MLD及主动脉CT值差异无统计学意义(P>0.05),EI、SD与SNR差异有统计学意义(P<0.05),常规剂量FBP组与低剂量KARL迭代重建组各定量指标差异均无统计学意义(P>0.05)。与常规剂量FBP组相比,低剂量FBP组EI高估1.66%(P<0.05),KARL迭代重建组EI高估0.68%(P>0.05)。结论KARL迭代重建的低剂量CT可用于COPD患者定量测量,KARL迭代重建技术在降低噪声、提高SNR的同时,在一定程度上提高了CT定量测量EI的准确性。Objective To investigate the effect of KARL iterative reconstruction algorithm on the quantitative index of emphysema in patients with chronic obstructive pulmonary disease(COPD)under low-dose and standard-dose scanning.Methods We prospectively recruited 30 patients(25 males and 5 females)with COPD with pulmonary nodules who underwent pulmonary function diagnosis from June 2018 to March 2019.The uCT-760128-slice spiral CT was used on the 30 patients to perform standard-dose(120 kV,150 mAs)scan for the first time,and the patients who came for reexamination underwent low-dose(120kV,80mAs)scan.We used filtered back projection(FBP)for standard-dose CT scan and FBP and KARL iterative reconstruction(IR)for the low-dose scan.We calculated the effective radiation dose(ED),the ascending aortic CT value and noise(SD)at the pulmonary bifurcation level,and the signal-to-noise ratio(SNR).Three sets of scan raw data were imported into the“digital lung”detection and analysis platform to calculate emphysema index(EI),total lung volume(LV)and total lung mean lung density(MLD).Paired sample t-test was used to analyze the differences between CT value,SD,SNR and CT quantitative index.The Bland-Altman analysis calculated the mean measurement deviation of emphysema index and the consistency of the two measurements.Results The standard-dose and low-dose effective radiation dose were(6.91±0.53)mSv and(3.71±0.28)mSv,respectively,a decrease of about 47%,with a significant difference(P<0.001).There were no significant differences in LV,MLD or aortic CT value between the standard-dose CT with FBP reconstruction and the low-dose CT with FBP reconstruction(P>0.05).EI,SD and SNR differed significantly(P<0.05).There were no significant differences in the quantitative indexes between the low-dose CT with KARL IR and standard-dose CT with FBP(P>0.05).Compared with the standard-dose CT with FBP,the EI of the low-dose CT with FBP was overestimated 1.66%.The difference was statistically significant(P<0.05).The EI of the low-dose CT with KARL I

关 键 词：滤波反投影(FBP) KARL迭代 肺气肿体素指数 噪声 低剂量 

分 类 号：R445.3[医药卫生—影像医学与核医学] R563.3[医药卫生—诊断学]