Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes significantly limits assessment . Vagal nerve stimulator device projects over the left lower chest wall with catheter extending into the left neck , unchanged in position from prior exam . Bronchovascular crowding at the lung bases noted . Heart size difficult to assess . No gross signs of pneumonia or overt CHF . No large effusion or pneumothorax is seen .
    OUTPUT:
    
Limited , negative .