Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is stable left lower lobe atelectasis . Otherwise , the lungs are clear . The heart size is top normal . The hilar and mediastinal contours are normal . There is no pneumothorax or pleural effusion . The pulmonary vascular markings are normal .
    OUTPUT:
    
Unchanged left basilar atelectasis . No marked change from prior study .