Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a left basilar retrocardiac opacity which obscures the left heart border . This may reflect atelectasis , though a consolidation due to infection or aspiration is not excluded . Otherwise , the lungs are clear without pleural effusion , pneumothorax or pulmonary edema . The cardiac silhouette is normal in size . The mediastinal and hilar contours are normal . Cervical spinal fusion hardware is partially visualized .
    OUTPUT:
    
Left basilar retrocardiac opacity obscuring the left heart border may reflect atelectasis , though consolidation can not be excluded .