Imaging-based clusters in former smokers of the COPD cohort associate with clinical characteristics: the SubPopulations and intermediate outcome measures in COPD study (SPIROMICS)
Imaging-based clusters in former smokers of the COPD cohort associate with clinical characteristics: the SubPopulations and intermediate outcome measures in COPD study (SPIROMICS)
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DOI：
10.1186/s12931-019-1121-z
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发表时间：
2019-07-15
影响因子：
5.8
通讯作者：
Lin, Ching-Long
中科院分区：
文献类型：
--
作者：
Haghighi, Babak;Choi, Sanghun;Lin, Ching-Long
基于定量计算机断层扫描（QCT）成像的指标能够量化吸烟引起的疾病改变，并为当前吸烟者识别基于成像的群集。我们的目标是通过降维和聚类方法获得具有临床意义的前吸烟者亚组，以开发一种新的COPD表型方法。方法采用影像学聚类分析方法对406例戒烟者进行影像学指标综合分析，其中影像学指标包括75项。它们包括10个节段和5个大叶位置的结构和功能变量。结构变量包括肺形态、分支角度、气道圆度、气道壁厚、气道直径；功能变量包括局部通气量、肺气肿百分比、功能性小气道疾病百分比、雅可比矩阵（体积变化）、各向异性变形指数（体积变化的方向偏好）、吸气和呼气时的组织分数。结果我们得到了四种不同的基于成像的簇作为可能的表型，分别为100、80、141和85。第1组受试者无症状，除气道壁增厚和中度肺气肿外，气道结构和肺功能相对正常。第2组肥胖女性受试者吸气时组织分数增加，肺气肿最小，肺气肿进展率最低。第3组受试者为老年男性，呼气时气道狭窄，组织分数下降，均表明空气捕获。第4组以瘦弱男性为主的受试者可能是肺气肿进展率最高的重度COPD受试者。结论：基于sqct成像的前吸烟者指标允许推导与独特临床特征相关的统计稳定簇。这种方法有助于更好地对COPD亚群进行分类；提示可能的定量结构和功能表型。
BackgroundQuantitative computed tomographic (QCT) imaging-based metrics enable to quantify smoking induced disease alterations and to identify imaging-based clusters for current smokers. We aimed to derive clinically meaningful sub-groups of former smokers using dimensional reduction and clustering methods to develop a new way of COPD phenotyping.MethodsAn imaging-based cluster analysis was performed for 406 former smokers with a comprehensive set of imaging metrics including 75 imaging-based metrics. They consisted of structural and functional variables at 10 segmental and 5 lobar locations. The structural variables included lung shape, branching angle, airway-circularity, airway-wall-thickness, airway diameter; the functional variables included regional ventilation, emphysema percentage, functional small airway disease percentage, Jacobian (volume change), anisotropic deformation index (directional preference in volume change), and tissue fractions at inspiration and expiration.ResultsWe derived four distinct imaging-based clusters as possible phenotypes with the sizes of 100, 80, 141, and 85, respectively. Cluster 1 subjects were asymptomatic and showed relatively normal airway structure and lung function except airway wall thickening and moderate emphysema. Cluster 2 subjects populated with obese females showed an increase of tissue fraction at inspiration, minimal emphysema, and the lowest progression rate of emphysema. Cluster 3 subjects populated with older males showed small airway narrowing and a decreased tissue fraction at expiration, both indicating air-trapping. Cluster 4 subjects populated with lean males were likely to be severe COPD subjects showing the highest progression rate of emphysema.ConclusionsQCT imaging-based metrics for former smokers allow for the derivation of statistically stable clusters associated with unique clinical characteristics. This approach helps better categorization of COPD sub-populations; suggesting possible quantitative structural and functional phenotypes.