Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . Lung volumes are low limiting assessment . Subtle perihilar opacities likely represent bronchovascular crowding though difficult to exclude a component of mild congestion . No definite signs of pneumonia , effusion or pneumothorax . The heart size appears within normal limits . The mediastinal contour is normal . The bony structures are intact .
    OUTPUT:
    
Perihilar opacity and bronchovascular crowding though difficult to exclude a component of mild congestion .