Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy and CABG . Mild enlargement of the cardiac silhouette with left ventricular predominance is again demonstrated . The aorta remains mildly tortuous . The pulmonary vascularity is normal . Patchy opacity is noted within the left lung base , findings which could reflect atelectasis though aspiration is not excluded . No large pleural effusion or pneumothorax is visualized . Old right 6th rib fracture is present .
    OUTPUT:
    
Left basilar patchy opacification could reflect atelectasis though aspiration can not be excluded .