Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is no focal consolidation , effusion , or pneumothorax . There is mild bibasilar atelectasis . The cardiomediastinal silhouette is normal . Imaged osseous structures are intact . No free air below the right hemidiaphragm is seen . Left upper lobe opacity overlying the first rib is questionable for a nodule . Linear opacities in the lingula and right middle lobe could be due to infection .
    OUTPUT:
    
Linear opacities in the lingula and right middle lobe could be due to infection .