Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A left - sided Port - A - Cath terminates at the cavoatrial junction , unchanged from the prior study . The cardiomediastinal and hilar contours are within normal limits and stable from the prior exam . A left basal opacity is similar in character to the prior radiograph and likely represents a layering left pleural effusion and adjacent atelectasis . There is no pneumothorax identified . The osseous structures are grossly normal .
    OUTPUT:
    
Left basal opacity is consistent with a small to moderate left layering pleural effusion and adjacent atelectasis . Infection in that area should be considered in the appropriate clinical setting .