Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A single AP radiograph of the chest was acquired . Lung volumes are slightly low , causing accentuation of the pulmonary vasculature and exaggeration of the heart size . The lungs are clear . Heart size is top normal . The mediastinal contours are normal . No pleural effusions . No pneumothorax .
    OUTPUT:
    
Low lung volumes . No acute cardiac or pulmonary process .