Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph obtained . Lung volumes are low with bronchovascular crowding , likely accounting for the subtle lower lung opacities . There is no definite sign of pneumonia or CHF . No pleural effusion or pneumothorax is seen . The heart and mediastinal contours appear normal . Bony structures are intact .
    OUTPUT:
    
No signs of pneumonia . Limited exam due to low lung volumes .