Quantitative computed tomography of the lungs and airways in healthy nonsmoking adults.
Quantitative computed tomography of the lungs and airways in healthy nonsmoking adults.
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DOI：
10.1097/rli.0b013e318262292e
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发表时间：
2012-10
影响因子：
6.7
通讯作者：
COPDGene Investigators
中科院分区：
文献类型：
--
作者：
Zach JA;Newell JD Jr;Schroeder J;Murphy JR;Curran-Everett D;Hoffman EA;Westgate PM;Han MK;Silverman EK;Crapo JD;Lynch DA;COPDGene Investigators
本研究的目的是评估健康非吸烟成人肺衰减定量CT （QCT）测量和气道参数测量的正常范围，并确定这些测量变化的来源和可能的调整方法。在COPDGene®研究中，92名健康的非西班牙裔白人非吸烟者[29名男性，63名女性，平均年龄62.7 (SD 9.0), BMI 28.1 (SD 5.1)]在完全吸气和正常呼气结束时接受了体积CT检查。在QCT分析（肺工作站2，VIDA Diagnostics）中，吸气低衰减区定义为吸气CT （LAAI-950）上衰减值≤-950 Hounsfield Units （HU）的肺组织。呼气低衰减区定义为呼气CT (LAAE-856)≤-856 HU的肺组织。我们使用简单线性回归来确定年龄和性别对QCT参数的影响，并使用多元回归来评估CT （TLCCT和FRCCT）测量的总肺活量和功能剩余容量、扫描仪类型和平均气管空气衰减的附加影响。采用气道壁厚（AWT）、内腔面积（ILA）、壁厚百分比（WA%）和内周长为10mm的气道标准化厚度（Pi10）对气道进行评估。laae -950平均%为2.0 (SD 2.7)， LAAE-856平均%为9.2 （SD 6.8）。LAAI-950的平均%男性为3.6 (SD 3.2) %，女性为1.3 (SD 2.0) % （P<0.001）。LAAI-950百分比随年龄（P=0.08）和BMI （P=0.52）无显著变化。%LAAE-856与年龄（P=0.33）、性别（P=0.70）或BMI （P=0.32）无独立关系。多因素分析显示，%LAAI-950与TLCCT呈正相关（P=0.002），与平均气管空气衰减呈负相关（P=0.003）， %LAAE-856与年龄（P=0.001）、FRCCT （P=0.007）和扫描仪类型相关（P<0.001）。多因素分析显示，ILA和WA%与TLCCT （P<0.001）和年龄（0.006）显著相关。WA%还与性别（P=0.05）、轴向像元大小（P=0.03）和切片间隔（P=0.04）相关。最后，AWT受轴向像素大小的强烈影响（P<0.001）。虽然正常肺的衰减特征因年龄和性别而异，但这些差异在多变量分析中并不持续存在。基于衰减的定量CT参数测量的潜在变异来源包括吸入/呼气深度和扫描仪类型。气管空气衰减可以部分纠正扫描仪类型引起的变化。QCT气道测量差异的来源可能包括年龄、性别、BMI、吸气深度和空间分辨率。
The purposes of this study are to evaluate the normal range of quantitative CT (QCT) measures of lung attenuation and airway parameters measurements in healthy non-smoking adults and to identify sources of variation in those measures and possible means to adjust for them. Within the COPDGene® study, 92 healthy non-Hispanic White non-smokers [29 male, 63 female, mean age 62.7 (SD 9.0), BMI 28.1 (SD 5.1)] underwent volumetric CT at full inspiration and at the end of a normal expiration. On QCT analysis (Pulmonary Workstation 2, VIDA Diagnostics), inspiratory low attenuation areas were defined as lung tissue with attenuation values ≤ −950 Hounsfield Units (HU) on inspiratory CT (LAAI-950). Expiratory low attenuation areas were defined as lung tissue ≤ −856 HU on expiratory CT (LAAE-856). We used simple linear regression to determine the impact of age and gender on QCT parameters and multiple regression to assess the additional impact of total lung capacity and functional residual capacity measured by CT (TLCCT and FRCCT), scanner type, and mean tracheal air attenuation. Airways were evaluated using measures of airway wall thickness (AWT), inner luminal area (ILA), wall area percent (WA%) and standardized thickness of an airway with inner perimeter of 10mm (Pi10). Mean %LAAI-950 was 2.0 (SD 2.7), and mean %LAAE-856 was 9.2 (SD 6.8). Mean %LAAI-950 was 3.6 (SD 3.2) % in men, compared with 1.3 (SD 2.0) in women (P<0.001). The %LAAI-950 did not change significantly with age (P=0.08) or BMI (P=0.52). %LAAE-856 did not show any independent relationship with age (P=0.33), gender (P=0.70), or BMI (P=0.32). On multivariate analysis, %LAAI-950 showed a direct relationship to TLCCT (P=0.002) and an inverse relationship to mean tracheal air attenuation (P=0.003), and %LAAE-856 was related to age (P=0.001), FRCCT (P=0.007) and scanner type (P<0.001). Multivariate analysis of segmental airways showed that ILA and WA% were significantly related to TLCCT (P<0.001) and age (0.006). WA% was also associated with gender (P=0.05), axial pixel size (P=0.03) and slice interval (P=0.04). Lastly, AWT is strongly influenced by axial pixel size (P<0.001). Although the attenuation characteristics of normal lung differ by age and gender, these differences do not persist on multivariate analysis. Potential sources of variation in measurement of attenuation-based quantitative CT parameters include depth of inspiration/expiration, and scanner type. Tracheal air attenuation may partially correct variation due to scanner type. Sources of variation in QCT airway measurements may include age, gender, BMI, depth of inspiration, and spatial resolution.