Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single portable AP view of the chest . Linear opacity at the left lung base laterally is suggestive of atelectasis versus scarring , unchanged . Elsewhere the lungs are clear . There is no pneumothorax . The cardiomediastinal silhouette is within normal limits . Osseous structures demonstrate no acute abnormality .
    OUTPUT:
    
No acute cardiopulmonary process .