Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is moderate cardiomegaly . Widened right sided mediastinum , prominence of the aortic arch and irregularity along the wall of the descending aorta is secondary to known aortic dissection . Lungs are essentially clear . There is mild atelectasis at the lung bases bilaterally . There is no focal consolidation , large pleural effusion or pneumothorax .
    OUTPUT:
    
Widened mediastinum on the right , secondary to known aortic dissection . Lungs are essentially clear .