Fig. 1

Computed tomographic images of the retrograde systemic to pulmonary artery shunt. A Numerous neovascular vessels in the left chest wall (red arrow). B Anomalous arteries in the left lower lobe superior segment of lung (Lt. S6, red arrow). C Filling defect in the left apical segmental pulmonary artery of the left lower lobe (Lt. A6, red arrow). D In the three-dimension (3D) image, the 4th intercostal artery, a systemic artery, flowed into the left apical segmental pulmonary artery of the left lower lobe (Lt. A6), which was diagnosed as the systemic-to-pulmonary artery shunt (SPAS)