Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A linear opacity at the left base is similar to the prior exam . Given the chronicity , this is likely chronic atelectasis or scarring . There is no new opacity to suggest pneumonia . There is no pulmonary edema , pleural effusion , or pneumothorax . The cardiomediastinal silhouette is normal .
    OUTPUT:
    
No acute cardiopulmonary process , specifically , no evidence of pneumonia .