Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy and CABG . Heart size is mildly enlarged . Mediastinal and hilar contours are unchanged . The pulmonary vasculature is not engorged . No focal consolidation , pleural effusion or pneumothorax is present . Retrocardiac streaky opacity likely reflects atelectasis . There are no acute osseous abnormalities . Clips in the right upper quadrant of the abdomen indicate prior cholecystectomy .
    OUTPUT:
    
Streaky retrocardiac opacity , likely atelectasis .