Splenic Vein and Portal Vein

It is important to remember that the appearances of the splenic vein and the portal vein are complicated by the IVC running on the right, and the left renal vein crossing the aorta below the superior mesenteric artery (SMA).
The splenic vein crosses the aorta above the SMA (image below left).

Furthermore, the portal vein crosses both the aorta and IVC (image below right).