Partial anomalous pulmonary venous return

Partial anomalous pulmonary venous return of the left upper lobe to a mediastinal left vertical vein that joins the left brachiocephalic vein and creates a left to right shunt.
(A) Computed tomography (CT) of the thorax with axial, maximum intensity projection demonstrating a truncated left superior pulmonary vein (thin arrow).
(B) Axial, contrast-enhanced CT shows the junction of the left vertical vein with the left brachiocephalic vein (arrowhead).
(C) Axial, contrast-enhanced CT shows the vertical vein (dashed arrow).
(D) Multiplanar coronal reformation demonstrates the vertical vein in the mediastinum (thick arrow).