Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear unchanged . The lung volumes are low . There is no pleural effusion or pneumothorax . Blunting of the left costophrenic sulcus on the frontal view suggests minor atelectasis . Otherwise , the lungs appear clear . A right internal central jugular venous catheter is somewhat difficult to follow in the mediastinum but it appears to terminate in the superior vena cava .
    OUTPUT:
    
No evidence of acute disease .