Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The inspiratory lung volumes are appropriate . The lungs are clear without focal consolidation , pleural effusion or pneumothorax . The cardiomediastinal and hilar structures are within normal limits . There is no pneumomediastinum . Subtle lucency along the posterior margin of the trachea and middle mediastinum may represent superimposed shadows although pneumomediastinum can not be entirely excluded . The trachea is midline . No acute osseous abnormality is detected .
    OUTPUT:
    
No pneumopericardium . Subtle linear lucencies on the lateral view may represent superimposed shadows but pneumomediastinum can not be entirely excluded .