Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs and pleural spaces are essentially clear without evidence of pneumothorax or pleural effusions . Redemonstration of right hilar prominence likely reflects an enlarged right pulmonary artery as seen on prior CT and x-ray . Heart size is within upper limits of normal . There is tortuosity of the thoracic aorta . Retrocardiac opacity is stable and likely reflects underlying atelectasis . Osseous structures are grossly unchanged .
    OUTPUT:
    
No acute intrathoracic process . Stable prominence to the right perihilar region that likely reflects enlargement of the right pulmonary artery .