Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest . After review of multiple chest radiographs , there is persistent relatively increased translucency and decreased vascular markings at both lung bases concerning for basal emphysema . The heart , mediastinum , hila , and pleural surfaces are normal . There is no evidence of pneumonia .
    OUTPUT:
    
1 . No evidence of pneumonia . 2 . Persistent increased bibasilar translucency concerning for possible basal emphysema . Alpha 1 antitrypsin deficiency is a possible etiology of basal emphysema .