Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Mild enlargement of the cardiac silhouette is unchanged . The mediastinal and hilar contours are within normal limits . Pulmonary vasculature is normal . Streaky retrocardiac opacity likely reflects atelectasis . No focal consolidation , pleural effusion or pneumothorax is present . Moderate multilevel degenerative changes are again seen in the thoracic spine .
    OUTPUT:
    
Streaky retrocardiac opacity most likely reflective of atelectasis .