Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size , mediastinal and hilar contours are within normal limits . Lung volumes are slightly low . Lungs are grossly clear , and there are no pleural effusions , pneumothoraces or acute skeletal findings . However , extreme left lateral ribs have been excluded from the radiograph and are not fully assessed .
    OUTPUT:
    
No evidence of pneumonia , pleural effusion , or pneumothorax .