慢性阻塞性肺疾病肺气肿改变的CT评估——不同层厚及卷积函数重建对其与肺功能相关性的影响  

Computed tomography for emphysema evaluation in chronic obstructive pulmonary disease patients： the impact of section thickness and reconstruction kernel

作　　者：程挺[1] 程齐俭[1] 周敏[1] 杨文洁[2] 过依[1] 冯耘[1] 范亮[1] 戴然然[1] 丁永杰[1] 李庆云[1] 黄绍光[1] 万欢英[1] 

机构地区：[1]上海交通大学医学院附属瑞金医院呼吸科,上海200025 [2]上海交通大学医学院附属瑞金医院放射科,上海200025

出　　处：《实用放射学杂志》2013年第9期1419-1425,共7页Journal of Practical Radiology

基　　金：上海申康医院发展中心慢性病综合防治项目（SHDC12012305）;科技部＂十一五＂支撑课题（2008BAI52B00）.

摘　　要：目的 探讨不同层厚及卷积函数重建下慢性阻塞性肺疾病肺气肿改变的CT评估与肺功能相关性.方法 入选慢性阻塞性肺疾病（COPD）稳定期患者36例,完成肺功能,胸部深吸气相CT扫描.CT扫描在64排CT上进行,以层厚0.625 mm,1.25 mm,5 mm,7.5 mm,10 mm进行标准重建,以层厚0.625 mm,1.25 mm进行高频重建.用影思软件对全肺CT进行三维重建,在-1 020^-830 HU,每间隔10 HU设一阈值,共20个,分别计算CT值低于该阈值的低密度区比例（LAA%）,并进行视觉评分.观察这些指标与肺功能的相关性.结果 LAA%随CT层厚变薄及重建锐度升高而增加.LAA%与第1 s用力呼气容积（FEV1）,FEV1占预计的百分比（FEV1%pred）,FEV1占用力肺活量的比例（FEV1/FVC）,最大中段呼气流量占预计值的百分比（MMEF%pred）,总弥散量占预计值的百分比（DLCO%pred）,单位弥散量占预计值的百分比（DLCO/VA%pred）等肺功能指标相关性较好,P＆lt;0.05.本研究给出各层厚及重建方式下与各指标相关性最好的LAA%判定阈值及相关性.其中FEV1%pred与层厚1.25 mm高频重建,以-930 HU为阈值所得LAA%相关性最好,相关系数-0.588,P=0.001.软件自动计算的LAA%与肺功能的相关性优于视觉肺气肿评分.结论 COPD低密度区比例LAA%与患者的肺功能相关,其最佳阈值及相关性受层厚及重建卷积函数的影响.Objective To study the applicability of computed tomography {CT） for emphysema evaluation in chronic obstructive pulmonary disease （COPD） patients and the effect of section thickness and reconstruction kernel. Methods Thirty six COPD pa tients underwent chest CT （deep inspiratory phase} and lung function test. CT images were reconstructed using 7 different combina- tions of section thickness and reconstruction kernel （section thickness： 0. 625 ram, 1.25 ram, 5 mm, 7.5 mm, and 10 ram; recon- struction algorithms： standard and bone）. Three-dimensional reconstruction and quantitative analysis was performed using the Myri- an software. I.ow attenuation area percent （LAA~） was determined as the percentage of lung pixels showing attenuation lower than 20 thresholds ranging from 1020 HU to --830 HU. Visual scoring was done by a radiologist and a pulmonologist independently. The correlation between these indexes was analyzed. Results LAA% increased when section thickness became smaller or when the bone algorithm was used instead of the standard algorithrru LAA% was related to lung function （FE＇V1,FEV1% predicted,FEV1/FVC, MMEF%pred , DLCO%pred , and DLCO/VA% pred） . This study rendered the best threshold of LAA% to correlate with the index of lung function test in every common combination of section thickness and reconstruction kernel ,and the corresponding correlation. The LAA% that best correlated with FEV10% pred was observed at the section thickness of 1.25 mm while using the bone algorithm with the threshold of -930 HU （r =-0. 588, P= 0. 001）. Compared to the visual scoring, that LAA% calculated using a software correlated better with lung function. Conclusion LAA% correlated with the lung function of COPD patients. The section thickness and reconstruction kernel had an effect on best threshold and correlation

关 键 词：慢性阻塞性肺疾病 肺气肿 计算机体层成像 层厚 重建算法 肺功能 

分 类 号：R563[医药卫生—呼吸系统] R563.3[医药卫生—内科学]