Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A single portable AP chest radiograph was obtained . Low lung volumes accentuate the interstitium and pulmonary vascular markings . The azygos vein is dilated . Cardiac and mediastinal contours are normal . No focal consolidation , effusion , or pneumothorax is present .
    OUTPUT:
    
Dilated azygous vein indicates increased pulmonary vascular pressure . Most of the interstitial markings on this exam , however , are more attributable to low lung volumes .