Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well expanded and clear . The cardiac silhouette is normal . The mediastinal silhouette shows an unfolded or dilated ascending aorta , but one unchanged since at least ___ . The hilar contours and pleural surfaces are normal . No pleural effusion or pneumothorax is present . There is mild bilateral acromioclavicular osteoarthritis .
    OUTPUT:
    
No acute intrathoracic process .