Objective        To investigate the dynamic chest CT characteristics of pulmonary alveolar proteinosis (PAP) and its clinical significance.       Methods        The CT findings and clinical data were reviewed in 15 patients with PAP

including 6 males and 9 females with the age of 17-53 years (37.8 years on average). Twelve patients were confirmed by clinical data and bronchoalveolar lavage

and 3 patients were confirmed pathologically by bronchoscopy or percutaneous lung biopsy. Chest CT scanning was performed for 26 times in the 15 patients

including 7 patients receiving chest CT scanning once

5 patients receiving chest CT scanning twice and 3 patients receiving chest CT scanning for 3 times

respectively. All the patients were examined for pulmonary function. Bronchoalveolar lavage (BAL) was performed for 34 times in 10 patients

with 1-6 times  for each patient. Seven patients underwent follow-up chest CT scanning after BAL.       Results       Diffuse pulmonary consolidation or ground glass opacity was observed in all the patients

with “crazy paving” sign in 13 times of chest CT scanning

thickened interlobular septa in 12 times of chest CT scanning

and pulmonary fibrosis in 9 times of chest CT scanning. The lung lesions distributed heterogeneously in most cases and appeared as “geographic pattern”. In the follow-up chest CT after BAL

lung lesions relieved obviously

and the disease extent diminished and the density decreased.       Conclusion       The typical CT characteristics of PAP are diffuse pulmonary consolidation

ground glass opacity and “crazy paving” sign. Dynamic CT scanning before and after BAL is helpful for the diagnosis and therapeutic evaluation of PAP.