Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest demonstrate a stable postoperative appearance of the left hemithorax status post thoracoplasty . Right apical scarring persists . Right lung base opacity partially obscuring right hemidiaphragm is new since prior exam . Ill - defined left lung base opacity is also noted . No pleural effusion is seen . There is no pulmonary edema . Emphysema predominantly involving upper lung zones is unchanged . Hilar and mediastinal silhouettes are stable . Heart size is normal . Partially imaged upper abdomen is unremarkable .
    OUTPUT:
    
Bibasilar opacities are new since ___ exam , possibly atelectasis , aspiration , or infection in appropriate clinical setting .