Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low leading to crowding of the bronchovascular structures . Left retrocardiac atelectasis versus aspiration has improved as compared to the prior examination . There is no lobar consolidation , large pleural effusion , or pneumothorax . The cardiomediastinal silhouette is unchanged .
    OUTPUT:
    
Low lung volumes and improving left retrocardiac atelectasis versus aspiration .