Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Linear opacities within the left lung base may represent areas of subsegmental atelectasis or scarring . Atelectasis has a non-specific appearance though can sometimes be a finding in acute pulmonary embolism in a patient presenting with chest pain . Aspiration or pneumonia are also possible in the appropriate clinical setting . The remainder of the lungs are clear . There is no vascular congestion or pleural effusions . No pneumothorax is identified . Cardiomediastinal and hilar contours are within normal limits .
    OUTPUT:
    
Linear opacity in the left lower lobe , probably subsegmental atelectasis . However , in the appropriate clinical context , this may represent focal pneumonia or aspiration . Dr . ___ communicated the above findings to Dr . ___ at 8 :01 am on ___ by telephone .