Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: As compared to prior chest x-ray , persists left lung base opacity , compatible with atelectasis , but reduced since ___ . The lung is otherwise clear and well inflated with flattening of the hemidiaphragm and hyperlucency at the upper lobes consistent with chronic pulmonary disease . Cardiomediastinal silhouette is unchanged and normal . There is no pleural effusion or pneumothorax . Mild kyphosis is unchanged .
    OUTPUT:
    
Persistant minimal atelectasis at the left lung base , improved since ___ . Mild emphysema .