Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single portable AP chest radiograph was obtained . Low lung volumes accentuate interstitial markings and the pulmonary vasculature . Despite these limitations , the lungs are clear . No nodule , consolidation , effusion , or pneumothorax is present . The heart and mediastinal contours are normal .
    OUTPUT:
    
Low lung volumes .