Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . Mediastinal and hilar contours are unremarkable . There is normal pulmonary vascularity . Patchy opacity is demonstrated within the left lung base , with minimal streaky opacity in the right lung base . No pneumothorax or pleural effusion is demonstrated . There are no acute osseous abnormalities .
    OUTPUT:
    
Patchy left basilar opacity may reflect atelectasis though infection is not excluded . Right basilar atelectasis .