Fleischner sign and Palla sign in pulmonary embolism

(A) Chest radiograph shows enlargement and abrupt tapering of the right interlobar pulmonary artery (arrow). This finding is known as the Fleischner sign or Palla sign.

(B) CT scan demonstrates a large embolus within the right interlobar pulmonary artery (arrow).

CT: computed tomography.

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