Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is mildly enlarged . The aorta is mildly tortuous . Mediastinal and hilar contours are otherwise unremarkable . Pulmonary vasculature is normal . Streaky retrocardiac opacity likely reflects atelectasis . No focal consolidation , pleural effusion or pneumothorax is otherwise demonstrated . No acute osseous abnormality is seen . There are mild degenerative changes in the thoracic spine .
    OUTPUT:
    
Streaky retrocardiac opacity , likely atelectasis .