Abstract

Computed tomography (CT) total-airway-count (TAC) and airway wall-thickness differ across chronic obstructive pulmonary disease (COPD) severities, but longitudinal insights are lacking. The aim of this study was to evaluate longitudinal CT airway measurements over three-years in ex-smokers. In this prospective convenience sample study, ex-smokers with (n = 50; 13 female; age = 70 ± 9 years; pack-years = 43 ± 26) and without (n = 40; 17 female; age = 69 ± 10 years; pack-years = 31 ± 17) COPD completed CT, ³He magnetic resonance imaging (MRI), and pulmonary function tests at baseline and three-year follow-up. CT TAC, airway wall-area (WA), lumen-area (LA), and wall-area percent (WA%) were generated. Emphysema was quantified as the relative-area-of-the-lung with attenuation < –950 Hounsfield-units (RA₉₅₀). MRI ventilation-defect-percent (VDP) was also quantified. Differences over time were evaluated using paired-samples t tests. Multivariable prediction models using the backwards approach were generated. After three-years, forced-expiratory-volume in 1-second (FEV₁) was not different in ex-smokers with (p = 0.4) and without (p = 0.5) COPD, whereas RA₉₅₀ was (p < 0.001, p = 0.02, respectively). In ex-smokers without COPD, there was no change in TAC (p = 0.2); however, LA (p = 0.009) and WA% (p = 0.01) were significantly different. In ex-smokers with COPD, TAC (p < 0.001), WA (p = 0.04), LA (p < 0.001), and WA% (p < 0.001) were significantly different. In all ex-smokers, TAC was related to VDP (baseline: ρ = –0.30, p = 0.005; follow-up: ρ = –0.33, p = 0.002). In significant multivariable models, baseline airway wall-thickness was predictive of TAC worsening. After three-years, in the absence of FEV₁ worsening, TAC diminished only in ex-smokers with COPD and airway walls were thinner in all ex-smokers. These longitudinal findings suggest that the evaluation of CT airway remodeling may be a useful clinical tool for predicting disease progression and managing COPD.

Clinical trial registration: www.clinicaltrials.gov NCT02279329

摘要

计算机断层扫描 (CT) 总气道计数 (TAC) 和气道壁厚度因慢性阻塞性肺疾病 (COPD) 的严重程度而异，但缺乏纵向洞察。本研究的目的是评估戒烟者三年来的纵向 CT 气道测量结果。在这项前瞻性便利样本研究中，戒烟者（n  = 50；13 名女性；年龄 = 70 ± 9 岁；烟包年数 = 43 ± 26）和未戒烟者（n  = 40；17 名女性；年龄 = 69 ± 10 岁） ；包年 = 31 ± 17) COPD 完成 CT，³他在基线和三年随访时进行了磁共振成像（MRI）和肺功能测试。生成 CT TAC、气道壁面积 (WA)、管腔面积 (LA) 和壁面积百分比 (WA%)。_{肺气肿被量化为衰减 < –950 Hounsfield 单位 (RA 950} )的肺相对面积。MRI 通气缺陷百分比 (VDP) 也进行了量化。使用配对样本t检验评估随时间变化的差异。使用向后方法生成了多变量预测模型。三年后，患有 ( p  = 0.4) 和不患有 ( p  = 0.5) COPD 的戒烟者的 1 秒用力呼气量 (FEV ₁ ) 没有差异，而 RA ₉₅₀则为 ( p = 0.4) < 0.001，p  = 0.02，分别）。在没有 COPD 的戒烟者中，TAC 没有变化 ( p  = 0.2)；然而，LA ( p  = 0.009) 和 WA% ( p  = 0.01) 存在显着差异。在患有 COPD 的戒烟者中，TAC ( p  < 0.001)、WA ( p  = 0.04)、LA ( p  < 0.001) 和 WA% ( p  < 0.001) 存在显着差异。在所有戒烟者中，TAC 与 VDP 相关（基线：ρ = –0.30，p  = 0.005；随访：ρ = –0.33，p = 0.002）。在重要的多变量模型中，基线气道壁厚度可以预测 TAC 恶化。三年后，在 FEV1 没有恶化的情况下_，只有患有慢性阻塞性肺病 (COPD) 的戒烟者的 TAC 有所下降，并且所有戒烟者的气道壁都变薄。这些纵向研究结果表明，CT 气道重塑的评估可能是预测疾病进展和管理 COPD 的有用临床工具。

临床试验注册： www.clinicaltrials.gov NCT02279329