Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest were reviewed and compared to the prior studies . Focal opacification in the left lower lung could represent atelectasis , aspiration or possibly saline infused during bronchoscopy . Otherwise the lungs are clear without evidence of pulmonary edema , vascular congestion , pleural effusion or pneumothorax . The cardiac and mediastinal contours are normal .
    OUTPUT:
    
Opacity in the left lower lung could represent atelectasis , aspiration or possibly normal saline used during bronchoscopy .