Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
Department of Clinical Pharmacology and Therapeutics, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
Int J Chron Obstruct Pulmon Dis. 2019 Jun 24;14:1333-1342. doi: 10.2147/COPD.S207267. eCollection 2019.
The diagnosis and severity of chronic obstructive pulmonary disease (COPD) are defined by airflow limitation using spirometry. However, COPD has diverse clinical features, and several phenotypes based on non-spirometric data have been investigated. To identify novel phenotypes of COPD using radiologic data obtained by three-dimensional computed tomography (3D-CT).
The inner luminal area and wall thickness of third- to sixth-generation bronchi and the percentage of the low-attenuation area (less than -950 HU) of the lungs were measured using 3D-CT in patients with COPD. Using the radiologic data, hierarchical clustering was performed. Respiratory reactance and resistance were measured to evaluate functional differences among the clusters.
Four clusters were identified among 167 patients with COPD: Cluster I, mild emphysema with severe airway changes, severe airflow limitation, and high exacerbation risk; Cluster II, mild emphysema with moderate airway changes, mild airflow limitation, and mild dyspnea; Cluster III, severe emphysema with moderate airway changes, severe airflow limitation, and increased dyspnea; and Cluster IV, moderate emphysema with mild airway changes, mild airflow limitation, low exacerbation risk, and mild dyspnea. Cluster I had the highest respiratory resistance among the four clusters. Clusters I and III had higher respiratory reactance than Clusters II and IV.
The 3D-CT-based radiologic phenotypes were associated with the clinical features of COPD. Measurement of respiratory resistance and reactance may help to identify phenotypic differences.
慢性阻塞性肺疾病（COPD）的诊断和严重程度是通过肺量计测量气流受限来定义的。然而，COPD 具有多种临床特征，已经研究了几种基于非肺量计数据的表型。使用三维计算机断层扫描（3D-CT）获得的放射学数据来确定 COPD 的新表型。
对 COPD 患者进行 3D-CT 检查，测量第 3 至 6 代支气管的内腔面积和壁厚度，以及肺部低衰减区（低于-950 HU）的百分比。使用放射学数据进行层次聚类。测量呼吸电抗和阻力，以评估聚类之间的功能差异。
在 167 例 COPD 患者中，发现了四个聚类：聚类 I，严重气道改变的轻度肺气肿，严重气流受限，高加重风险；聚类 II，轻度气道改变的轻度肺气肿，轻度气流受限，轻度呼吸困难；聚类 III，中度气道改变的严重肺气肿，严重气流受限，呼吸困难加重；聚类 IV，轻度气道改变的中度肺气肿，轻度气流受限，低加重风险，轻度呼吸困难。四个聚类中，聚类 I 的呼吸阻力最高。聚类 I 和聚类 III 的呼吸电抗高于聚类 II 和聚类 IV。
基于 3D-CT 的放射学表型与 COPD 的临床特征相关。测量呼吸阻力和电抗可能有助于识别表型差异。
