Li Xun, Naidoo Parm, Guy Paul, Finlay Paul, Foo Soo-Wei, Hamza Kais, Bardin Philp
Department of Respiratory and Sleep Medicine .
J Asthma. 2014 Apr;51(3):282-7. doi: 10.3109/02770903.2013.860165. Epub 2013 Dec 17.
It is not known how airway structure is altered during real-life acute asthma exacerbations. The aim of this study was to examine changes in airway structure during acute asthma exacerbations and at convalescence by using lung-volume controlled high resolution computerised tomography (HRCT).
Eight subjects with acute asthma exacerbation admitted to hospital were recruited. HRCT was performed within 72 h of admission (n = 8) and repeated after 8 weeks of convalescence (n = 7). Individual airways were carefully matched on acute and convalescent CT data sets for comparisons of airway parameters. A novel methodology was employed for standardisation of lung volumes to permit valid comparisons of lung imaging. Measurements of bronchial cross sectional airway area (Aa) and bronchial luminal area (Ai) for each matched airway were obtained using a validated program.
The airway wall thickness was analysed as wall area (WA) calculated as a percentage: WA% = WA/Aa × 100. Wilcoxon signed-rank testing was used to compare acute and convalescent asthma and Spearman's correlation to examine associations. Airway lumen (Ai) areas were similar in both acute and stable asthma phases (6.6 ± 3.1 mm(2) versus 7.2 ± 3.8 mm(2) p = 0.8). However, the airway wall was significantly thickened during acute asthma exacerbations compared to convalescence (62 ± 4% versus 55 ± 7%; p = 0.01). There was no correlation between airway structure dimensions and lung function measurements.
This is the first study to demonstrate an increase in airway wall thickness during real-life acute asthma exacerbation. However, narrowing of the airway lumen area was variable and will require larger studies able to detect small differences. These results suggest that airway wall thickening linked to mucosal inflammation is likely to characterise acute asthma in vivo but that changes in the airway lumen accompanying bronchoconstriction may be more heterogeneous.
目前尚不清楚在实际生活中的急性哮喘发作期间气道结构是如何改变的。本研究的目的是通过使用肺容积控制的高分辨率计算机断层扫描（HRCT）来检查急性哮喘发作期间和恢复期气道结构的变化。
招募了8名因急性哮喘发作入院的受试者。在入院72小时内进行HRCT（n = 8），并在恢复期8周后重复进行（n = 7）。在急性和恢复期CT数据集上仔细匹配个体气道，以比较气道参数。采用一种新的方法对肺容积进行标准化，以允许对肺部成像进行有效的比较。使用经过验证的程序获得每个匹配气道的支气管横截面积（Aa）和支气管腔面积（Ai）的测量值。
气道壁厚度以壁面积（WA）作为百分比进行分析：WA% = WA/Aa×100。采用Wilcoxon符号秩检验比较急性和恢复期哮喘，并使用Spearman相关性检验来检查相关性。急性和稳定期哮喘阶段的气道腔（Ai）面积相似（6.6±3.1mm²对7.2±3.8mm²，p = 0.8）。然而，与恢复期相比，急性哮喘发作期间气道壁明显增厚（62±4%对55±7%；p = 0.01）。气道结构尺寸与肺功能测量值之间无相关性。
这是第一项证明在实际生活中的急性哮喘发作期间气道壁厚度增加的研究。然而，气道腔面积的缩小是可变的，需要更大规模的研究来检测微小差异。这些结果表明，与黏膜炎症相关的气道壁增厚可能是体内急性哮喘的特征，但支气管收缩伴随的气道腔变化可能更加异质性。
