Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal silhouette is unremarkable . Lung volumes are low and an opacity at the left lung base likely represents platelike atelectasis . The thoracic aorta is mildly tortuous . There is no pneumothorax or pleural effusion . Osseous structures are unremarkable .
    OUTPUT:
    
No acute cardiopulmonary abnormality .