Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are normally expanded except for some mild atelectasis at the left base . No focal airspace opacity to suggest pneumonia . The cardiomediastinal silhouette , hilar contours , and pleural surfaces are normal . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Mild atelectasis at the left base . Otherwise , no evidence of acute cardiopulmonary abnormality .