Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Allowing for differences in technique , the cardiac , mediastinal and hilar contours appear stable . There is no evidence for pneumomediastinum , or pneumothorax . There is possibly a trace pleural effusion on the left only . The lungs appear clear . There is no free air .
    OUTPUT:
    
Suspected trace pleural effusion on the left ; otherwise unremarkable .