Abstract: Objective To explore the value of quantitative analysis of emphysema with chest high-resolution computed tomography (HRCT) in the elderly patients with severe chronic obstructive pulmonary disease (COPD)who couldn’t tolerate pulmonary function tests (PFT). Methods A total of 85 hospitalized patients with COPD were enrolled in this study. According to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines, all patients were classified into four groups: GOLD Ⅰ,Ⅱ,Ⅲ and Ⅳ, and comparative analysis of demographic characteristics, blood gas analysis, blood routine and LAA%_-950HU was conducted among the four groups. Ordered multinomial Logistic regression was employed to analyze the related risk factors of GOLD classification. ROC curve was drawn to investigate the predictive value of various indicators for GOLD Ⅳ. Results Duration of COPD, arterial oxygen partial pressure (PaO₂), arterial carbon dioxide partial pressure (PaCO₂), and the percentage of low attenuation area below -950 HU (LAA%_-950HU) were significantly different among the four groups (P＜0.05). Logistic regression analysis indicated that GOLD classification was positively correlated with duration of COPD, PaCO₂ and LAA%_-950HU , but negatively correlated with peripheral blood eosinophil count. Receiver operating characteristic curve analysis showed that the areas under the curve of LAA%_-950HU and PaCO₂ in predicting GOLD grade Ⅳ were 0.751 and 0.870, and the cut-off values were 34.8% and 42.5 mmHg, respectively. Conclusions The pulmonary function in the elderly COPD patients with severe airflow restriction who could not tolerate the PFT can be evaluated based on LAA%_-950HU and PaCO₂, which have certain clinical value for the formulation and adjustment of treatment.

Key words: chronic obstructive pulmonary disease, high-resolution computed tomography, low attenuation area