Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were obtained . Mild patchy left base opacity is seen , which may be in the lingula , could be atelectasis ; however , infection is not excluded . No pleural effusion or pneumothorax is seen . The cardiac and mediastinal silhouettes are stable .
    OUTPUT:
    
Subtle left base , possibly lingular opacity may relate to atelectasis , although infection is not excluded in the appropriate clinical setting .