Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well expanded with linear opacities in the left lung base suggestive of atelectasis or scarring , also seen on previous chest CTs . The lateral left lung and left costophrenic angle are not included on the frontal view . No consolidative opacity to suggest pneumonia . No pulmonary edema . Mediastinal contours , hila , and cardiac silhouette are normal . No pneumothorax or large pleural effusion .
    OUTPUT:
    
Left basilar opacity likely atelectasis . Infection not excluded .