Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A Port - A - Cath terminates at the cavoatrial junction . A nasogastric tube passes into the stomach . Part of a biliary drain projects over the epigastric region . The cardiac , mediastinal , and hilar contours appear unchanged . The lung volumes are low . There is no pleural effusion or pneumothorax . Streaky retrocardiac opacity is most suggestive of atelectasis .
    OUTPUT:
    
Patchy opacity on the left which may be due to atelectasis , probably unchanged .