Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single AP upright portable chest radiograph obtained . Low lung volumes significantly limit the evaluation . Allowing for this , bronchovascular crowding likely accounts for the relative increase in bronchovascular opacities in the lower lungs . No definite sign of pneumonia , pleural effusion , or pneumothorax . Cardiomediastinal silhouette is stable with top normal heart size . Bony structures are intact . No free air below the right hemidiaphragm .
    OUTPUT:
    
Limited , negative .