Abstract: Objective To qualitatively evaluate the right ventricular function and the pulmonary artery obstruction degree in patients of acute pulmonary embolism (APE) with computed tomographic pulmonary angiography (CTPA).Methods Retrospective assessment was made in 75 APE patients, mean age (59.2±13.3) years; range 25-80 years; 33 women. CT pulmonary angiography examinations were performed in the patients. CT pulmonary artery obstruction scores (OS) were used in the assessment of pulmonary arterial obstruction severity. All patients were divided into mild (n=18), moderate (n=25), or severe groups (n=32) according to OS <30%, 30%-50%, ≥50% respectively. Right ventricular function was assessed on CT in all patients by measuring right ventricular short axis diameter(RVd), left ventricular short axis diameter (LVd), RVd to LVd(RVd/LVd) ratio, main pulmonary artery, azygos vein, superior vena cava diameters. Also, these CT parameters for right ventricular function were compared among three groups.Results The correlation between CT pulmonary artery OS and cardiovascular parameters was significant (P<0.01). The cardiovascular parameters including RVd, RVd/LVd ratio, main pulmonary artery diameter, azygos vein diameter, superior vena cava diameter in patients with moderate and severe APE (OS 30%-50% and OS≥50%, respectively) were higher than those with mild APE (OS<30%) (P<0.05). And LVd in patients with moderate and severe APE was lower than that with mild APE (P<0.05). In the meantime, comparison of cardiovascular parameters between patients with moderate and severe APE showed significant differences (P<0.05).Conclusion Quantitative CT parameters prove useful in evaluating the right ventricular function and the pulmonary artery obstruction degree in APE, and there was significant correlation between the right ventricular function and the pulmonary artery obstruction degree.