An important and specific sonographic finding in patients with portal hypertension is the presence of portosystemic collaterals. Collaterals may be classified as either tributary collaterals, that is, normally existing collaterals or developed collaterals, which are normally closed channels that open in the setting of portal hypertension. Normally existing collaterals include the coronary (left gastric), short gastric, superior mesenteric, and inferior mesenteric veins (figure 2). Because of improvements in technology, the coronary vein can be seen in some normal patients, however, its diameter should be 6 mm and flow should be hepatopetal (towards the liver). When flow is hepatofugal (away from the liver) patients are at increased risk for a variceal bleed.
