上海交通大学学报（医学版）

上海交通大学学报（医学版）

• 论著（临床研究） • 上一篇    下一篇

4种评估肺气肿的CT指标的比较及层厚和重建方式的影响

程挺1，李勇1，程齐俭1，杨文洁2，万欢英1   

  1. 上海交通大学 医学院 1．附属瑞金医院北院呼吸内科， 上海 201801； 2．附属瑞金医院放射科，上海 200025
  • 出版日期:2015-11-28 发布日期:2016-01-13
  • 通讯作者: 程齐俭, 电子信箱: chengqijian@aliyun.com。
  • 作者简介:程挺(1988—)， 男， 住院医师， 博士; 电子信箱: chengting425@126.com。
  • 基金资助:

    上海申康医院发展中心慢性病综合防治项目（SHDC12012305）；上海交通大学医学院附属瑞金医院北院研究基金（2015ZY04）

Comparison of four CT indexes for evaluation of emphysema and effects of section thickness and reconstruction algorithm

CHENG Ting1, LI Yong1, CHENG Qi-jian1, YANG Wen-jie2, WAN Huan-ying1   

  1. 1.Department of Respiratory Medicine， Ruijin Hospital North， Shanghai Jiao Tong University School of Medicine, Shanghai 201801, China； 2.Department of Radiology， Ruijin Hospital， Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
  • Online:2015-11-28 Published:2016-01-13
  • Supported by:

    Chronic Disease Prevention and Treatment Program of Shanghai Hospital Development Center, SHDC12012305； Research Foundation of Ruijin Hospital North, Shanghai Jiao Tong University School of Medicine， 2015ZY04

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摘要：

目的  探讨在慢性阻塞性肺疾病（COPD）患者中，评估肺气肿各CT指标与肺功能的相关性，分析层厚和重建方式对其的影响。方法  入选COPD稳定期患者39例，完成肺功能各项检测和吸气相胸部CT扫描。CT图像以层厚0.625、1.25、5、7.5和10 mm进行标准重建，以层厚0.625 mm和1.25mm进行高频重建。用最佳阈值及默认阈值测量低衰减区比例（LAA%）、全肺像素CT值直方图上第15百分位点对应的CT值（Perc 15）、平均肺密度和全肺体积。分析不同层厚和重建方式对这些指标的影响，以及这些指标与肺功能的相关性。 结果  LAA%随层厚增大而减小，高频重建高于标准重建。Perc 15、平均肺密度随层厚增加升高，高频重建低于标准重建。而全肺体积的测量所受影响较小。在各层厚及重建方式下，第1秒用力呼气容积（FEV1）、FEV1占预计值的百分比（FEV1%pred）、FEV1占用力肺活量（FVC）的比例（FEV1/FVC）、最大呼气中段流量占预计值的百分比（MMEF%pred）、一氧化碳弥散量（DLCO）、DLCO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）与LAA%呈负相关（P<0.05），与Perc 15呈正相关（P<0.05）。FEV1%pred、FEV1/FVC与平均肺密度呈正相关（P<0.05）。肺总量（TLC）、残气量（RV）、残总比（RV/TLC）与CT所示全肺体积呈正相关（P<0.05）。对于肺通气指标和弥散指标，LAA%和Perc 15与其的相关性高于平均肺密度和全肺体积。对于肺容积指标，CT所示全肺体积高于其他参数。层厚对肺气肿CT评估结果和肺功能的相关性影响不大；而LAA%、Perc 15与部分肺通气指标（如FEV1）的相关性，高频重建高于标准重建。结论  在胸部CT中测算LAA%、Perc15能较好反映肺功能中的通气和弥散指标，CT所示全肺体积能较好反映肺功能中的容积指标。进行CT肺气肿评估时，应注意层厚、重建方式的同一性，若有不同，需进行相应修正。

关键词: 慢性阻塞性肺疾病, 肺气肿, CT, 层厚, 重建方式

Abstract:

Objective  To explore the correlation between CT indexes of emphysema and lung function of patients with chronic obstructive pulmonary disease (COPD) and effects of section thickness and reconstruction algorithms. Methods  Thirty-nine COPD patients at stable phase were selected and underwent chest CT (deep inspiratory phase) and lung function test. CT images were reconstructed by standard algorithm with section thicknesses of 0.625, 1.25, 5, 7.5, and 10 mm and by bone algorithm with section thicknesses of 0.625 and 1.25 mm. Low attenuation area percent (LAA%), the lowest 15th percentile of the histogram of attenuation values (Perc 15), mean lung density, and lung volume were measured using the best threshold and default threshold. The effects of different section thicknesses and reconstruction algorithms on indexes and the correlation between indexes and lung function were analyzed. Results  LAA% decreased with the increase of section thickness and bone algorithm was higher than standard algorithm. Perc 15 and mean lung density increased with the increase of section thickness and bone algorithm was lower than standard algorithm, while section thickness and algorithm had little effect on the measurement of lung volume. For each section thickness and reconstruction algorithm, FEV1, FEV1%pred, FEV1/FVC, MMEF%pred, DLCO, DLCO%pred, DLCO/VA%pred negatively correlated with LAA% (P<0.05) and positively correlated with Perc 15 (P<0.05). FEV1%pred and FEV1/FVC positively correlated with mean lung density (P<0.05). RV, TLC, and RV/TLC positively correlated with lung volume on CT (P<0.05). For pulmonary ventilation indexes and diffusing capacity, their correlations with LAA% and Perc 15 were higher than those with mean lung density and lung volume. For lung volume indexes, the correlations with lung volume on CT were higher than those with other parameters. The section thickness did not have obvious effect on the correlation between CT assessment of emphysema and lung function. The correlations between LAA% or Perc 15 and some pulmonary ventilation index (such as FEV1) of bone reconstruction were higher than those of standard reconstruction. Conclusion  LAA% and Perc 15 measured from chest CT images can ideally reflect the ventilation indexes and diffusing capacity of lung function. The lung volume on CT can ideally reflect the volume indexes of lung function. Attention should be paid to the consistency of section thickness and reconstruction algorithm when performing CT emphysema evaluation and comparison. Modifications are needed if inconsistency exists.

Key words: chronic obstructive pulmonary disease, pulmonary emphysema, CT, section thickness, restruction algorithm