impressions
      right lung
            arch of azygous vein
            heart (right atrium)
            diaphragm
            esophagus
            subclavian artery
            superior vena cava
      left lung
            arch of aorta
                  2nd view
            heart (left ventricle)
            descending aorta
                  2nd view
            diaphragm
            esophagus
            subclavian artery