Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Chest PA and lateral radiograph demonstrates unremarkable mediastinal , hilar , and cardiac contours . Faint focal opacification at the left lung base is seen , although is not substantiated on the lateral view . No pleural effusion or pneumothorax is evident .
    OUTPUT:
    
Faint opacity at the left lung base may relate to atelectasis , and is not clearly substantiated on the lateral view , but early consolidation / infection not excluded in the appropriate clinical settng .