Objective      To explore the manifestations and clinical significance of chest CT images in microscopic polyangiitis (MPA) patients before pulmonary hemoptysis.       Methods      Clinical data and chest CT images of 30 patients diagnosed with MPA in First People’s Hospital of Ziyang City from January 2013 to September 2015 were analyzed retrospectively. Depending on clinical manifestations

the 30 cases of MPA were divided into 11 cases of pulmonary hemoptysis group and 19 cases of non-pulmonary hemoptysis group. The characteristics of CT images and clinical data of patients with hemoptysis before pulmonary hemoptysis were analyzed and compared with those of the patients without hemoptysis.       Results      All CT images were abnormal in 30 cases of MPA

including 13 cases of patchy opacities (43.3%)

8 cases of lung consolidations (26.7%)

13 cases of ground glass opacities (43.3%)

14 cases of reticular opacities (46.7%)

20 cases of pleural effusions (66.7%)

15 cases of emphysema (50%)

11 cases of mediastinal adenopathies (36.7%)

9 cases of bronchial dilatation (30%)

1 case of empty opacities (3.3%)

7 cases of leaflet septal thickening opacities (23.3%)

2 cases of nodular opacities (6.7%)

and 25 cases of fiber stripe opacities (83.3%). Patchy opacities

lung consolidations

ground glass opacities

and reticular opacities were more common in the pulmonary hemoptysis group than in the non-pulmonary hemoptysis group (P0.05). The patients in the hemoptysis group had hemoptysis at different degrees in 2 to 14 d after the abnormal CT images were observed. Chest pain

cough

expectoration

short breath and inflammation index were more common in the pulmonary hemoptysis group than in the non-pulmonary hemoptysis group (P0.05).       Conclusion      The hemoptysis may happen in the MPA patients with chest pain

cough

expectoration

short breath and elevated inflammation index when the CT images show patchy opacities

lung consolidations

ground glass opacities and reticular opacities.