Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph is obtained . Lung volumes are low which somewhat limits the evaluation . The heart size appears stable and normal . Bronchovascular crowding likely accounts for subtle opacities in the lower lungs . Otherwise lungs appear well aerated . No pleural effusion or pneumothorax . Mediastinal contour is normal . Bony structures are intact .
    OUTPUT:
    
Low lung volumes with no signs of CHF or pneumonia .