Xuesong Chen,1,* Kouying Liu,1,* Zhiyue Wang,2 Yinsu Zhu,2 Yang Zhao,3 Hui Kong,1 Weiping Xie,1 Hong Wang1 1Department of Respiratory Medicine, 2Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, 3Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, People’s Republic of China *These authors contributed equally to this work Abstract: Computed tomography (CT) is widely used for evaluation of lung diseases. To evaluate the value of CT measurement of pulmonary artery for diagnosis of chronic obstructive pulmonary disease (COPD) and its comorbidity pulmonary hypertension (PH), we retrospectively reviewed the CT of 221 patients with COPD and 115 control patients without cardiovascular or lung disease. Patients with COPD were divided into PH (COPD-PH) and non-PH according to systolic pulmonary artery pressure. Main pulmonary artery (MPA), right pulmonary artery (RPA) and left pulmonary artery branches, and ascending aorta (AAo) and descending aorta (DAo) diameters were measured. Meanwhile, the ratios of MPA/AAo and MPA/DAo were calculated. MPA, RPA, and left pulmonary artery diameters were significantly larger in COPD than those in the controls, and this augment was more obvious in COPD-PH. AAo and DAo diameters did not vary obviously between groups, while MPA/AAo and MAP/DAo increased significantly in COPD and PH. MPA could be helpful for COPD diagnosis (MPA diameter ≥27.5 mm, sensitivity 54%, and specificity 80%), and RPA could be applied for COPD-PH diagnosis (RPA diameter ≥23.4 mm, sensitivity 67%, and specificity 76%). There was a marked correlation between MPA/DAo and systolic pulmonary artery pressure (r=0.594, P<0.001). Therefore, chest CT could be a simple and effective modality for diagnostic evaluation of COPD and its comorbidity, PH. Keywords: computed tomography, chronic obstructive pulmonary disease, pulmonary hypertension, vessel measurement