Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well inflated and clear . Marked prominence of the aortic knob is concerning for underlying aneurysm versus dissection . Heart is normal in size . There is no pneumothorax or pleural effusion . Bony structures appear intact .
    OUTPUT:
    
Prominence of the aortic knob raises potential concern for aneurysm or dissection . CTA of the chest is recommended for further evaluation .