Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Residual left lower lobe opacity likely reflects subsegmental atelectasis in this patient with recent pneumonia . Please note a component of residual infection is difficult to exclude . Otherwise , the lungs appear clear . No large effusion or pneumothorax . The cardiomediastinal silhouette is unchanged . Bony structures are intact .
    OUTPUT:
    
Residual left lower lobe linear opacity likely represents atelectasis though can not exclude a component of pneumonia .