基于体素的COPD表型研究
Phenotypic study of COPD using voxel-based morphometry

摘要：目的 基于体素的定量CT筛选慢性阻塞性肺疾病(chronic obstructive pulmonary disease, COPD)影像学表型。方法 连续纳入“数字肺”多中心研究中行双气相扫描的COPD患者，定量测定小气道病变(functional small-airway disease, fSAD)和肺气肿(emphysema, Emph)。采用k-means聚类法分析肺气肿和小气道病变，得到不同表型；采用Fisher判别分析得到分类函数，并进行初始验证和交叉验证。结果 共纳入COPD患者50例。在所有患者及肺功能近似相同的慢性阻塞性肺疾病全球倡议(The Global Initiative for Chronic Obstructive Lung Disease, GOLD)2级患者中均得到3种不同表型：肺气肿为主型、小气道病变为主型及混合型，以及3种表型的Fisher线性分类函数；对所得函数进行初始验证和交叉验证，所有COPD患者预测分类结果的正确率分别为92.0%及90.0%，GOLD 2 级患者预测分类结果的正确率分别为100.0%及95.2%。结论 基于体素的定量CT可以将COPD患者分为肺气肿为主型、小气道病变为主型及混合型。
ABSTRACT: Objective To screen phenotypes of chronic obstructive pulmonary disease (COPD) using the voxel-based quantitative CT. Methods COPD patients who had received inspiratory and expiratory CT scanning were consecutively recruited from the multi-center study named Digital Lung. Quantitative parametres of functional small-airway disease (fSAD) and emphysema (Emph) were measured. The k-means clustering method was used to analyze the different phenotypes using the paramenters of emphysema and small-airway disease. Fisher discriminatory analysis was used to get the classification function, and then make initial and cross validation. Results Totally 50 COPD patients were recuited. We obtained three phenotypes in the whole cohort and the The Global Initiative for Chronic Obstructive Lung Disease (GOLD) II patients with the similar lung function, namely, emphysema-dominant type, small airway disease-dominant type, and the mixed type. Fisher linear classification function of the three phenotypes were obtained. In the initial verification and cross validation, the correct rate of the whole COPD subjects were 92.0% and 90.0%, the correct rate of GOLD 2 grade patients were 100.0% and 95.2%, respectively. Conclusion The voxel-based quantitative CT can be used to divide COPD patients into three imaging phenotypes, namely, emphysema-dominant type, small airway disease-dominant type, and mixed type