Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is linear opacity at the left lung base laterally on the frontal view . Elsewhere , the lungs are clear . There is no effusion or pneumothorax . The cardiomediastinal silhouette is within normal limits .
    OUTPUT:
    
Left base opacity laterally , potentially atelectasis ; however , clinical correlation regarding possibility of infection is suggested .