Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy and CABG . Mediastinal contour is unchanged with marked tortuosity of the aorta . Focal convexity of the right superior mediastinal border is compatible with prominent vasculature as seen on the previous CT . Pulmonary vasculature is not engorged . Streaky opacities within the retrocardiac region likely reflect areas of atelectasis . No pleural effusion or pneumothorax is present . Partially imaged is an aortic stent within the upper abdomen . No acute osseous abnormality is seen .
    OUTPUT:
    
Minimal streaky retrocardiac opacity , likely atelectasis .