Multidetector CT anatomy of drainage routes of gastric varices: a pictorial review.

Most gastric varices arise at hepatofugal collateral pathways and drain into the systemic vein through one or both of two different types of portosystemic collateral drainage systems: the gastroesophageal (azygous) venous system and the gastrophrenic venous system. The gastroesophageal venous system consists of gastric varices contiguous with esophageal varices, paraesophageal varices, and the azygos vein, which terminates into the superior vena cava. Gastric varices draining through the gastroesophageal venous system can be treated with endoscopic techniques or creation of a transjugular intrahepatic portosystemic shunt. The gastrophrenic venous system consists of the gastric varices and the left inferior phrenic vein (IPV), which terminates into the left renal vein or the inferior vena cava. The left IPV has abundant anastomoses with peridiaphragmatic and retroperitoneal veins, and these anastomoses can function as drainage pathways from gastric varices. Balloon-occluded retrograde transvenous obliteration is a preferred treatment option for this type of gastric varix. Occasionally, gastric varices can form at the hepatopetal collateral pathway that develops secondary to localized portal hypertension caused by splenic vein occlusion. Splenectomy is often required for the treatment of this type of gastric varix. Multidetector computed tomography permits comprehensive evaluation of these venous drainage systems. Familiarity with and assessment of these draining routes of gastric varices are important for selecting treatment options and interventional techniques.