Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest . Linear opacity at the left lung base most suggestive of atelectasis versus scar given persistence . Elsewhere , the lungs are clear . There is no effusion or pneumothorax . The cardiomediastinal silhouette is within normal limits . Osseous structures demonstrate no acute abnormality .
    OUTPUT:
    
No acute cardiopulmonary process .