Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear without focal consolidation . No pleural effusion or pneumothorax is seen . Heart size is normal . Widened appearance of the mediastinum likely due to unfolded thoracic aorta , though dissection can not be excluded .
    OUTPUT:
    
Widened appearance of the mediastinum likely due to unfolded thoracic aorta . Aortic dissection can not be excluded on a conventional radiograph , but there are no findings to suggest that diagnosis on this study .